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75
201
Let the sequence $\{x_n\}$ be defined by $x_1 \in \{5, 7\}$ and, for $k \ge 1, x_{k+1} \in \{5^{x_k} , 7^{x_k} \}$. For example, the possible values of $x_3$ are $5^{5^5}, 5^{5^7}, 5^{7^5}, 5^{7^7}, 7^{5^5}, 7^{5^7}, 7^{7^5}$, and $7^{7^7}$. Determine the sum of all possible values for the last two digits of $x_{2012}$...
Let the sequence $\{x_n\}$ be defined by $x_1 \in \{5, 7\}$ and, for $k \ge 1, x_{k+1} \in \{5^{x_k} , 7^{x_k} \}$. For example, the possible values of $x_3$ are $5^{5^5}, 5^{5^7}, 5^{7^5}, 5^{7^7}, 7^{5^5}, 7^{5^7}, 7^{7^5}$, and $7^{7^7}$. Determine the sum of all possible values for the last two digits of $x_{2012}$...
75
dapo_math
1940
202
Find the number of ordered quadruples of positive integers \((a,b,c,d)\) such that \(a,b,c,\) and \(d\) are all (not necessarily distinct) factors of \(30\) and \(abcd > 900\).
Find the number of ordered quadruples of positive integers \((a,b,c,d)\) such that \(a,b,c,\) and \(d\) are all (not necessarily distinct) factors of \(30\) and \(abcd > 900\).
1940
dapo_math
6
203
复数 $z^{11}+z=1$,求 $z$ 的一个正确的幂次形式。答案应为 $z^k$ 的形式,请给出 $k$ 的值。
复数 $z^{11}+z=1$,求 $z$ 的一个正确的幂次形式。答案应为 $z^k$ 的形式,请给出 $k$ 的值。
6
dapo_math
4018
204
Let $\omega$ be a nonreal root of $x^3 = 1,$ and let \[\mathbf{M} = \begin{pmatrix} -\omega^2 & - \omega \\ 1 & 0 \end{pmatrix}.\]Find the sum of the entries of $\mathbf{M} + \mathbf{M}^2 + \mathbf{M}^3 + \dots + \mathbf{M}^{2009}.$
Let $\omega$ be a nonreal root of $x^3 = 1,$ and let \[\mathbf{M} = \begin{pmatrix} -\omega^2 & - \omega \\ 1 & 0 \end{pmatrix}.\]Find the sum of the entries of $\mathbf{M} + \mathbf{M}^2 + \mathbf{M}^3 + \dots + \mathbf{M}^{2009}.$
4018
dapo_math
109
205
Ryan has 3 red lava lamps and 3 blue lava lamps. He arranges them in a row on a shelf randomly, and then randomly turns 3 of them on. What is the probability that the leftmost lamp is blue and off, and the rightmost lamp is red and on?The answer is in the form rac{m}{n}, where gcd(m, n) = 1. Please provide the value o...
Ryan has 3 red lava lamps and 3 blue lava lamps. He arranges them in a row on a shelf randomly, and then randomly turns 3 of them on. What is the probability that the leftmost lamp is blue and off, and the rightmost lamp is red and on?The answer is in the form rac{m}{n}, where gcd(m, n) = 1. Please provide the value o...
109
dapo_math
48
206
Equilateral triangle \(ABC\) has been creased and folded so that vertex \(A\) now rests at \(A'\) on \(\overline{BC}\) as shown. If \(BA' = 1\) and \(A'C = 2\), then find the length of the crease \(\overline{PQ}\). The original answer is in the form \(\frac{k}{m}\sqrt{n}\), please give the value of k + m + n.
Equilateral triangle \(ABC\) has been creased and folded so that vertex \(A\) now rests at \(A'\) on \(\overline{BC}\) as shown. If \(BA' = 1\) and \(A'C = 2\), then find the length of the crease \(\overline{PQ}\). The original answer is in the form \(\frac{k}{m}\sqrt{n}\), please give the value of k + m + n.
48
dapo_math
561
207
What are the last three digits of $49^{303} \cdot 3993^{202} \cdot 39^{606}$?
What are the last three digits of $49^{303} \cdot 3993^{202} \cdot 39^{606}$?
561
dapo_math
0
208
Find the imaginary part of \[(\cos12^\circ+i\sin12^\circ+\cos48^\circ+i\sin48^\circ)^6.\]
Find the imaginary part of \[(\cos12^\circ+i\sin12^\circ+\cos48^\circ+i\sin48^\circ)^6.\]
0
dapo_math
25
209
Let u, f, and g be functions, defined for all real numbers x, such that $$\frac{u(x+1)+u(x-1)}{2}=f(x) \text { and } \frac{u(x+4)+u(x-4)}{2}=g(x).$$ Determine u(x) in terms of f and g. Please provide the value of u(x) when x = 1. The answer should be in the format $u(x)=g(a)-f(b)+f(c)-f(d)+f(e)$, directly give the valu...
Let u, f, and g be functions, defined for all real numbers x, such that $$\frac{u(x+1)+u(x-1)}{2}=f(x) \text { and } \frac{u(x+4)+u(x-4)}{2}=g(x).$$ Determine u(x) in terms of f and g. Please provide the value of u(x) when x = 1. The answer should be in the format $u(x)=g(a)-f(b)+f(c)-f(d)+f(e)$, directly give the valu...
25
dapo_math
5
210
Let $ABC$ be an acute triangle with side lengths $AB = 7$, $BC = 12$, $AC = 10$, and let $\omega$ be its incircle. If $\omega$ is touching $AB$, $AC$ at $F, E$, respectively, and if $EF$ intersects $BC$ at $X$, suppose that the ratio in which the angle bisector of $\angle BAC$ divides the segment connecting the midpoin...
Let $ABC$ be an acute triangle with side lengths $AB = 7$, $BC = 12$, $AC = 10$, and let $\omega$ be its incircle. If $\omega$ is touching $AB$, $AC$ at $F, E$, respectively, and if $EF$ intersects $BC$ at $X$, suppose that the ratio in which the angle bisector of $\angle BAC$ divides the segment connecting the midpoin...
5
dapo_math
6
211
How many positive cubes divide $3!\cdot 5!\cdot 7!\,$?
How many positive cubes divide $3!\cdot 5!\cdot 7!\,$?
6
dapo_math
20
212
What is the difference between the maximum value and the minimum value of the sum $a_1 + 2a_2 + 3a_3 + 4a_4 + 5a_5$ where $\{a_1,a_2,a_3,a_4,a_5\} = \{1,2,3,4,5\}$? Provide your answer as an integer.
What is the difference between the maximum value and the minimum value of the sum $a_1 + 2a_2 + 3a_3 + 4a_4 + 5a_5$ where $\{a_1,a_2,a_3,a_4,a_5\} = \{1,2,3,4,5\}$? Provide your answer as an integer.
20
dapo_math
231
213
定义 $x * y=\frac{x+y}{1+x y}$, 则 $(\cdots((2 * 3) * 4) \cdots) * 21$结果的格式为$\frac{m}{n}$,给出$m + n$的值。
定义 $x * y=\frac{x+y}{1+x y}$, 则 $(\cdots((2 * 3) * 4) \cdots) * 21$结果的格式为$\frac{m}{n}$,给出$m + n$的值。
231
dapo_math
26
214
Each of two boxes contains both black and white marbles, and the total number of marbles in the two boxes is $25.$ One marble is taken out of each box randomly. The probability that both marbles are black is $27/50,$ and the probability that both marbles are white is $m/n,$ where $m$ and $n$ are relatively prime positi...
Each of two boxes contains both black and white marbles, and the total number of marbles in the two boxes is $25.$ One marble is taken out of each box randomly. The probability that both marbles are black is $27/50,$ and the probability that both marbles are white is $m/n,$ where $m$ and $n$ are relatively prime positi...
26
dapo_math
10
215
Kelly drove north for 9 miles and then east for 12 miles at an average rate of 42 miles per hour to arrive at the town of Prime. Brenda left from the same location, at the same time, and drove along a straight road to Prime at an average rate of 45 miles per hour. How many minutes earlier than Kelly did Brenda arrive?
Kelly drove north for 9 miles and then east for 12 miles at an average rate of 42 miles per hour to arrive at the town of Prime. Brenda left from the same location, at the same time, and drove along a straight road to Prime at an average rate of 45 miles per hour. How many minutes earlier than Kelly did Brenda arrive?
10
dapo_math
457
216
The number $0.428125$ can be written as a fraction $\frac{a}{b}$ for positive integers $a$ and $b$. When this fraction is in simplest terms, what is $a+b$?
The number $0.428125$ can be written as a fraction $\frac{a}{b}$ for positive integers $a$ and $b$. When this fraction is in simplest terms, what is $a+b$?
457
dapo_math
165
217
Let $N=\overline{abc}$ be a three-digit number. It is known that we can construct an isosceles triangle with $a$, $b$, and $c$ as the lengths of sides. Determine how many possible three-digit numbers $N$ there are. ($N=\overline{abc}$ means that $a$, $b$, and $c$ are digits of $N$, and not $N=a \times b \times c$.)
Let $N=\overline{abc}$ be a three-digit number. It is known that we can construct an isosceles triangle with $a$, $b$, and $c$ as the lengths of sides. Determine how many possible three-digit numbers $N$ there are. ($N=\overline{abc}$ means that $a$, $b$, and $c$ are digits of $N$, and not $N=a \times b \times c$.)
165
dapo_math
17
218
称一个九位数是平衡的,如果数字 1\sim9 都出现. 将所有平衡的数按递增顺序依次写下,设 S 是所得的数字序列. 求最小的正整数 k,使得 S 的任意两个由 k 个连续数字构成的子列互不相同.
称一个九位数是平衡的,如果数字 1\sim9 都出现. 将所有平衡的数按递增顺序依次写下,设 S 是所得的数字序列. 求最小的正整数 k,使得 S 的任意两个由 k 个连续数字构成的子列互不相同.
17
dapo_math
12
219
For each positive integer $k$, let $S_k$ denote the increasing arithmetic sequence of integers whose first term is $1$ and whose common difference is $k$. For example, $S_3$ is the sequence $1,4,7,10,\ldots.$ For how many values of $k$ does $S_k$ contain the term $2005$?
For each positive integer $k$, let $S_k$ denote the increasing arithmetic sequence of integers whose first term is $1$ and whose common difference is $k$. For example, $S_3$ is the sequence $1,4,7,10,\ldots.$ For how many values of $k$ does $S_k$ contain the term $2005$?
12
dapo_math
13
220
Let $\Gamma_1$, $\Gamma_2$ be two circles, where $\Gamma_1$ has a smaller radius, intersecting at two points $A$ and $B$. Points $C$ and $D$ lie on $\Gamma_1$ and $\Gamma_2$ respectively such that point $A$ is the midpoint of the segment $CD$. Line $CB$ intersects the circle $\Gamma_2$ for the second time at point $F$,...
Let $\Gamma_1$, $\Gamma_2$ be two circles, where $\Gamma_1$ has a smaller radius, intersecting at two points $A$ and $B$. Points $C$ and $D$ lie on $\Gamma_1$ and $\Gamma_2$ respectively such that point $A$ is the midpoint of the segment $CD$. Line $CB$ intersects the circle $\Gamma_2$ for the second time at point $F$,...
13
dapo_math
286
221
对矩阵 P,定义 e^P=I+\ds{m=1}{\infty}\df{1}{m!}P^m. 设 20 阶实矩阵 A 满足 e^A=I_{20},且特征值的模长不超过 20,则这样的互不复相似的 A 有__________个.
对矩阵 P,定义 e^P=I+\ds{m=1}{\infty}\df{1}{m!}P^m. 设 20 阶实矩阵 A 满足 e^A=I_{20},且特征值的模长不超过 20,则这样的互不复相似的 A 有__________个.
286
dapo_math
41
222
Let $f(x) = x^3 + 3x^2 + 1$. There is a unique line of the form $y = mx + b$ such that $m > 0$ and this line intersects $f(x)$ at three points, $A, B, C$ such that $AB = BC = 2$. Find $\lfloor 100m \rfloor$.
Let $f(x) = x^3 + 3x^2 + 1$. There is a unique line of the form $y = mx + b$ such that $m > 0$ and this line intersects $f(x)$ at three points, $A, B, C$ such that $AB = BC = 2$. Find $\lfloor 100m \rfloor$.
41
dapo_math
33
223
设两个严格递增的正整数数列 $\left\{a_{n}\right\},\left\{b_{n}\right\}$ 满足: $a_{10}=b_{10}<2017$, 对任意正整数 $n$ ,有 $a_{n+2}=a_{n+1}+a_{n}, b_{n+1}=2 b_{n}$ ,请给出 $a_{1}+b_{1}$ 的所有可能值的和。
设两个严格递增的正整数数列 $\left\{a_{n}\right\},\left\{b_{n}\right\}$ 满足: $a_{10}=b_{10}<2017$, 对任意正整数 $n$ ,有 $a_{n+2}=a_{n+1}+a_{n}, b_{n+1}=2 b_{n}$ ,请给出 $a_{1}+b_{1}$ 的所有可能值的和。
33
dapo_math
102
224
Find the smallest positive three-digit integer $n$ such that $3^n + 4^n$ is divisible by $5$.
Find the smallest positive three-digit integer $n$ such that $3^n + 4^n$ is divisible by $5$.
102
dapo_math
14
225
The sum of the two $5$-digit numbers $AMC10$ and $AMC12$ is $123422$. What is the value of $A+M+C$?
The sum of the two $5$-digit numbers $AMC10$ and $AMC12$ is $123422$. What is the value of $A+M+C$?
14
dapo_math
3
226
What is the maximum possible value of $5 - |6x - 80|$ over all integers $x$?
What is the maximum possible value of $5 - |6x - 80|$ over all integers $x$?
3
dapo_math
220
227
Darwin takes an $11 \times 11$ grid of lattice points and connects every pair of points that are 1 unit apart, creating a $10 \times 10$ grid of unit squares. If he never retraced any segment, what is the total length of all segments that he drew?
Darwin takes an $11 \times 11$ grid of lattice points and connects every pair of points that are 1 unit apart, creating a $10 \times 10$ grid of unit squares. If he never retraced any segment, what is the total length of all segments that he drew?
220
dapo_math
8
228
Let $\mathbb{N}$ denote the set of all positive integers. Find a specific function $f: \mathbb{N} \rightarrow \mathbb{N}$ such that for $x = 1$ and $y = 1$, the expression $x^{2}-y^{2}+2 y(f(x)+f(y))$ becomes a square of an integer. Provide the value of $f(8)$.
Let $\mathbb{N}$ denote the set of all positive integers. Find a specific function $f: \mathbb{N} \rightarrow \mathbb{N}$ such that for $x = 1$ and $y = 1$, the expression $x^{2}-y^{2}+2 y(f(x)+f(y))$ becomes a square of an integer. Provide the value of $f(8)$.
8
dapo_math
22
229
A particular number written in base 3 requires three digits (${\_ \_ \_}_3$). When the number is written in base 3 and 4, the digits are the reverse of each other. What is this number expressed in base 10?
A particular number written in base 3 requires three digits (${\_ \_ \_}_3$). When the number is written in base 3 and 4, the digits are the reverse of each other. What is this number expressed in base 10?
22
dapo_math
16
230
Jack and Jill are playing a chance game. They take turns alternately rolling a fair six-sided die labeled with the integers 1 through 6 (fair meaning the numbers appear with equal probability). Jack wins if a prime number appears when he rolls, while Jill wins if a number greater than 1 appears when she rolls. The game...
Jack and Jill are playing a chance game. They take turns alternately rolling a fair six-sided die labeled with the integers 1 through 6 (fair meaning the numbers appear with equal probability). Jack wins if a prime number appears when he rolls, while Jill wins if a number greater than 1 appears when she rolls. The game...
16
dapo_math
30
231
Let $r$ be the number that results when both the base and the exponent of $a^b$ are tripled, where $a, b>0$. If $r$ equals the product of $a^b$ and $x^b$ where $x>0$, find the value of $x$. The original answer is in the form of $k \cdot m^n$, where $k$, $m$, and $n$ are constants. Please find the value of $k + m + n$.
Let $r$ be the number that results when both the base and the exponent of $a^b$ are tripled, where $a, b>0$. If $r$ equals the product of $a^b$ and $x^b$ where $x>0$, find the value of $x$. The original answer is in the form of $k \cdot m^n$, where $k$, $m$, and $n$ are constants. Please find the value of $k + m + n$.
30
dapo_math
132
232
For a real number $a$, let $\lfloor a \rfloor$ denote the greatest integer less than or equal to $a$. Let $\mathcal{R}$ denote the region in the coordinate plane consisting of points $(x,y)$ such that $\lfloor x \rfloor ^2 + \lfloor y \rfloor ^2 = 25$. The region $\mathcal{R}$ is completely contained in a disk of radiu...
For a real number $a$, let $\lfloor a \rfloor$ denote the greatest integer less than or equal to $a$. Let $\mathcal{R}$ denote the region in the coordinate plane consisting of points $(x,y)$ such that $\lfloor x \rfloor ^2 + \lfloor y \rfloor ^2 = 25$. The region $\mathcal{R}$ is completely contained in a disk of radiu...
132
dapo_math
810
233
On square $ABCD$, point $E$ lies on side $AD$ and point $F$ lies on side $BC$, so that $BE=EF=FD=30$. Find the area of the square $ABCD$.
On square $ABCD$, point $E$ lies on side $AD$ and point $F$ lies on side $BC$, so that $BE=EF=FD=30$. Find the area of the square $ABCD$.
810
dapo_math
64
234
Let $p(x) = x^{2008} + x^{2007} + x^{2006} + \cdots + x + 1,$ and let $r(x)$ be the polynomial remainder when $p(x)$ is divided by $x^4+x^3+2x^2+x+1$. Find the remainder when $|r(2008)|$ is divided by $1000$.
Let $p(x) = x^{2008} + x^{2007} + x^{2006} + \cdots + x + 1,$ and let $r(x)$ be the polynomial remainder when $p(x)$ is divided by $x^4+x^3+2x^2+x+1$. Find the remainder when $|r(2008)|$ is divided by $1000$.
64
dapo_math
720
235
A regular 12-gon is inscribed in a circle of radius 12. The sum of the lengths of all sides and diagonals of the 12-gon can be written in the form \[a + b \sqrt{2} + c \sqrt{3} + d \sqrt{6},\]where $a$, $b$, $c$, and $d$ are positive integers. Find $a+b+c+d$.
A regular 12-gon is inscribed in a circle of radius 12. The sum of the lengths of all sides and diagonals of the 12-gon can be written in the form \[a + b \sqrt{2} + c \sqrt{3} + d \sqrt{6},\]where $a$, $b$, $c$, and $d$ are positive integers. Find $a+b+c+d$.
720
dapo_math
19990002000
236
Find all positive integers $x$ for which there exists a positive integer $y$ such that $\dbinom{x}{y}=1999000$
Find all positive integers $x$ for which there exists a positive integer $y$ such that $\dbinom{x}{y}=1999000$
19990002000
dapo_math
167
237
Let $f : \mathbb{R} \to \mathbb{R}$ be a function satisfying the equation $f(x^2 + x + 3) + 2f(x^2 - 3x + 5) = 6x^2 - 10x + 17$ for all real numbers $x$. What is the value of $f(85)$?
Let $f : \mathbb{R} \to \mathbb{R}$ be a function satisfying the equation $f(x^2 + x + 3) + 2f(x^2 - 3x + 5) = 6x^2 - 10x + 17$ for all real numbers $x$. What is the value of $f(85)$?
167
dapo_math
7
238
若一个三角形的各边长均为整数且其面积为有理数,则该三角形某一边的长可以是以下哪些选项?计算这些选项的和 A. 1 B. 2 C. 3 D. 4
若一个三角形的各边长均为整数且其面积为有理数,则该三角形某一边的长可以是以下哪些选项?计算这些选项的和 A. 1 B. 2 C. 3 D. 4
7
dapo_math
36
239
There are positive integers that have these properties: $\bullet$ I. The sum of the squares of their digits is $50,$ and $\bullet$ II. Each digit is larger than the one on its left. What is the product of the digits of the largest integer with both properties?
There are positive integers that have these properties: $\bullet$ I. The sum of the squares of their digits is $50,$ and $\bullet$ II. Each digit is larger than the one on its left. What is the product of the digits of the largest integer with both properties?
36
dapo_math
872
240
For any set $S$, let $P(S)$ be its power set, the set of all its subsets. Consider all sets $A$ of 2015 arbitrary finite sets. Let $N$ be the maximum possible number of ordered pairs $(S,T)$ such that $S \in P(A)$, $T \in P(P(A))$, $S \in T$, and $S \subseteq T$. Note that by convention, a set may never contain itself....
For any set $S$, let $P(S)$ be its power set, the set of all its subsets. Consider all sets $A$ of 2015 arbitrary finite sets. Let $N$ be the maximum possible number of ordered pairs $(S,T)$ such that $S \in P(A)$, $T \in P(P(A))$, $S \in T$, and $S \subseteq T$. Note that by convention, a set may never contain itself....
872
dapo_math
37
241
设实数 $k, l, m$ 满足:函数 $y=(x+1)\left(x^{2}+k x+l\right)$ 的图像有对称中心 $(1,0)$ ,且与函数 $y=x^{3}+m$ 的图像有公共点, 则 $k+l+m$ 的取值范围是$\left(-\infty, \frac{a}{b}\right]$,求$a+b$的值。
设实数 $k, l, m$ 满足:函数 $y=(x+1)\left(x^{2}+k x+l\right)$ 的图像有对称中心 $(1,0)$ ,且与函数 $y=x^{3}+m$ 的图像有公共点, 则 $k+l+m$ 的取值范围是$\left(-\infty, \frac{a}{b}\right]$,求$a+b$的值。
37
dapo_math
5024
242
If $N=\lfloor \frac{2}{5} \rfloor + \lfloor \frac{2^2}{5} \rfloor + \dots + \lfloor \frac{2^{2009}}{5} \rfloor$, find the remainder when $2^{2010}$ is divided by $N$.
If $N=\lfloor \frac{2}{5} \rfloor + \lfloor \frac{2^2}{5} \rfloor + \dots + \lfloor \frac{2^{2009}}{5} \rfloor$, find the remainder when $2^{2010}$ is divided by $N$.
5024
dapo_math
7
243
Find the largest value of $t$ such that \[\frac{13t^2 - 34t + 12}{3t - 2 } + 5t = 6t - 1.\]The answer is in the form rac{m}{n}, where gcd(m, n) = 1. Please provide the value of m + n.
Find the largest value of $t$ such that \[\frac{13t^2 - 34t + 12}{3t - 2 } + 5t = 6t - 1.\]The answer is in the form rac{m}{n}, where gcd(m, n) = 1. Please provide the value of m + n.
7
dapo_math
4030
244
Let $a_1, a_2, a_3, \ldots$ be an infinite sequence where for all positive integers $i$, $a_i$ is chosen to be a random positive integer between $1$ and $2016$, inclusive. Let $S$ be the set of all positive integers $k$ such that for all positive integers $j < k$, $a_j \neq a_k$. (So $1 \in S$; $2 \in S$ if and only if...
Let $a_1, a_2, a_3, \ldots$ be an infinite sequence where for all positive integers $i$, $a_i$ is chosen to be a random positive integer between $1$ and $2016$, inclusive. Let $S$ be the set of all positive integers $k$ such that for all positive integers $j < k$, $a_j \neq a_k$. (So $1 \in S$; $2 \in S$ if and only if...
4030
dapo_math
140
245
The base three number $12012_3$ is equal to which base ten number?
The base three number $12012_3$ is equal to which base ten number?
140
dapo_math
125
246
Let $x=\frac{4}{(\sqrt{5}+1)(\sqrt[4]{5}+1)(\sqrt[8]{5}+1)(\sqrt[16]{5}+1)}.$ Find $(x+1)^{48}.$
Let $x=\frac{4}{(\sqrt{5}+1)(\sqrt[4]{5}+1)(\sqrt[8]{5}+1)(\sqrt[16]{5}+1)}.$ Find $(x+1)^{48}.$
125
dapo_math
3
247
求最小的实数 C,使得对任意正实数 a_1, a_2, a_3, a_4, a_5(允许相同),总可以选择不同的下标 i,j,k,l,满足 \left|\df{a_i}{a_j}-\df{a_k}{a_l}\right|\leq C.原始的答案是\frac{m}{n}的形式,其中m、n是互质的。请给出最终m + n的值
求最小的实数 C,使得对任意正实数 a_1, a_2, a_3, a_4, a_5(允许相同),总可以选择不同的下标 i,j,k,l,满足 \left|\df{a_i}{a_j}-\df{a_k}{a_l}\right|\leq C.原始的答案是\frac{m}{n}的形式,其中m、n是互质的。请给出最终m + n的值
3
dapo_math
7
248
Let $a_1, a_2, \ldots, a_n$ be real numbers, and let $b_1, b_2, \ldots, b_n$ be distinct positive integers. Suppose there is a polynomial $f(x)$ satisfying the identity $$(1-x)^n f(x)=1+\sum_{i=1}^n a_i x^{b_i}.$$ Find a simple expression (not involving any sums) for $f(1)$ in terms of $b_1, b_2, \ldots, b_n$ and $n$ (...
Let $a_1, a_2, \ldots, a_n$ be real numbers, and let $b_1, b_2, \ldots, b_n$ be distinct positive integers. Suppose there is a polynomial $f(x)$ satisfying the identity $$(1-x)^n f(x)=1+\sum_{i=1}^n a_i x^{b_i}.$$ Find a simple expression (not involving any sums) for $f(1)$ in terms of $b_1, b_2, \ldots, b_n$ and $n$ (...
7
dapo_math
24
249
Consider \(13\) marbles that are labeled with positive integers such that the product of all \(13\) integers is \(360\). Moor randomly picks up \(5\) marbles and multiplies the integers on top of them together, obtaining a single number. What is the maximum number of different products that Moor can obtain?
Consider \(13\) marbles that are labeled with positive integers such that the product of all \(13\) integers is \(360\). Moor randomly picks up \(5\) marbles and multiplies the integers on top of them together, obtaining a single number. What is the maximum number of different products that Moor can obtain?
24
dapo_math
81
250
If $x$ is a real number such that $3^x = 27x$, compute $\log_3 \left(\frac{3^{3^x}}{x^{3^3}}\right)$.
If $x$ is a real number such that $3^x = 27x$, compute $\log_3 \left(\frac{3^{3^x}}{x^{3^3}}\right)$.
81
dapo_math
9
251
已知 $\forall x \in R, f(x)=2 x^{4}+m x^{3}+(m+6) x^{2}+m x+2>0$, 求正整数 $m$ 的最大值。
已知 $\forall x \in R, f(x)=2 x^{4}+m x^{3}+(m+6) x^{2}+m x+2>0$, 求正整数 $m$ 的最大值。
9
dapo_math
671
252
The real numbers $a_0, a_1, \dots, a_{2013}$ and $b_0, b_1, \dots, b_{2013}$ satisfy the recurrence relations: \[ a_{n} = \frac{1}{63} \sqrt{2n+2} + a_{n-1} \quad \text{and} \quad b_{n} = \frac{1}{96} \sqrt{2n+2} - b_{n-1} \] for every integer $n = 1, 2, \dots, 2013$. Given the initial conditions $a_0 = b_{2013}$ and $...
The real numbers $a_0, a_1, \dots, a_{2013}$ and $b_0, b_1, \dots, b_{2013}$ satisfy the recurrence relations: \[ a_{n} = \frac{1}{63} \sqrt{2n+2} + a_{n-1} \quad \text{and} \quad b_{n} = \frac{1}{96} \sqrt{2n+2} - b_{n-1} \] for every integer $n = 1, 2, \dots, 2013$. Given the initial conditions $a_0 = b_{2013}$ and $...
671
dapo_math
4
253
求最小的实数 \lambda,使得对任意正实数 x_1,x_2,x_3,x_4,均存在 1, 2, 3, 4 的一个排列 \sigma,满足(x_{\sigma(1)}x_{\sigma(2)}-x_{\sigma(3)}x_{\sigma(4)})^2\leq\lambda\ds{1\leq i<j\leq 4}{}(x_i^2-x_j^2)^2.(Martin)原始的答案是\frac{m}{n}的形式,其中m、n是互质的。请给出最终m + n的值
求最小的实数 \lambda,使得对任意正实数 x_1,x_2,x_3,x_4,均存在 1, 2, 3, 4 的一个排列 \sigma,满足(x_{\sigma(1)}x_{\sigma(2)}-x_{\sigma(3)}x_{\sigma(4)})^2\leq\lambda\ds{1\leq i<j\leq 4}{}(x_i^2-x_j^2)^2.(Martin)原始的答案是\frac{m}{n}的形式,其中m、n是互质的。请给出最终m + n的值
4
dapo_math
715
254
$T$ is the smallest positive multiple of 14 whose digits are all 1s and 0s. What is the quotient when $T$ is divided by 14?
$T$ is the smallest positive multiple of 14 whose digits are all 1s and 0s. What is the quotient when $T$ is divided by 14?
715
dapo_math
1000
255
In the decimal expression of $1^1 + 2^2 + 3^3 + · · · + 999^{999} + 1000^{1000},$ what are its a) first three digits from the left? b) first four digits?
In the decimal expression of $1^1 + 2^2 + 3^3 + · · · + 999^{999} + 1000^{1000},$ what are its a) first three digits from the left? b) first four digits?
1000
dapo_math
1012
256
平面上有 2022 个点,满足任意三点不共线. 每个点被染为红色或蓝色,使得每三个(不同的)红点构成的三角形都至少包含一个蓝点. 求红点个数的最大可能值.
平面上有 2022 个点,满足任意三点不共线. 每个点被染为红色或蓝色,使得每三个(不同的)红点构成的三角形都至少包含一个蓝点. 求红点个数的最大可能值.
1012
dapo_math
15
257
A $2\times3$ rectangle has vertices at $(0,0)$, $(2,0)$, $(0,3)$, and $(2,3)$. It rotates $90^{\circ}$ clockwise about the point $(2,0)$. It then rotates $90^{\circ}$ clockwise about the point $(5,0)$, then $90^{\circ}$ clockwise about the point $(7,0)$, and finally, $90^{\circ}$ clockwise about the point $(10,0)$. (Th...
A $2\times3$ rectangle has vertices at $(0,0)$, $(2,0)$, $(0,3)$, and $(2,3)$. It rotates $90^{\circ}$ clockwise about the point $(2,0)$. It then rotates $90^{\circ}$ clockwise about the point $(5,0)$, then $90^{\circ}$ clockwise about the point $(7,0)$, and finally, $90^{\circ}$ clockwise about the point $(10,0)$. (Th...
15
dapo_math
2
258
After finding the average of $35$ scores, a student carelessly included the average with the $35$ scores and found the average of these $36$ numbers. The original answer is in the format k:m, where k and m are integers. Please find the value of k + m.
After finding the average of $35$ scores, a student carelessly included the average with the $35$ scores and found the average of these $36$ numbers. The original answer is in the format k:m, where k and m are integers. Please find the value of k + m.
2
dapo_math
499500
259
For positive integers $a$ and $N$, let $r(a, N) \in \{0, 1, \dots, N - 1\}$ denote the remainder of $a$ when divided by $N$. Determine the number of positive integers $n \le 1000000$ for which \[r(n, 1000) > r(n, 1001).\]
For positive integers $a$ and $N$, let $r(a, N) \in \{0, 1, \dots, N - 1\}$ denote the remainder of $a$ when divided by $N$. Determine the number of positive integers $n \le 1000000$ for which \[r(n, 1000) > r(n, 1001).\]
499500
dapo_math
0
260
Let $a,$ $b,$ $c,$ $d,$ and $e$ be the distinct roots of the equation $x^5 + 7x^4 - 2 = 0.$ Find \begin{align*} &\frac{a^3}{(a - b)(a - c)(a - d)(a - e)} + \frac{b^3}{(b - a)(b - c)(b - d)(b - e)} \\ &\quad + \frac{c^3}{(c - a)(c - b)(c - d)(c - e)} + \frac{d^3}{(d - a)(d - b)(d - c)(d - e)} \\ &\quad + \frac{e^3}{(e ...
Let $a,$ $b,$ $c,$ $d,$ and $e$ be the distinct roots of the equation $x^5 + 7x^4 - 2 = 0.$ Find \begin{align*} &\frac{a^3}{(a - b)(a - c)(a - d)(a - e)} + \frac{b^3}{(b - a)(b - c)(b - d)(b - e)} \\ &\quad + \frac{c^3}{(c - a)(c - b)(c - d)(c - e)} + \frac{d^3}{(d - a)(d - b)(d - c)(d - e)} \\ &\quad + \frac{e^3}{(e ...
0
dapo_math
1848
261
Two knights placed on distinct squares of an $8 \times 8$ chessboard, where each square is a unit square, are said to attack each other if the distance between the centers of the squares on which the knights lie is $\sqrt{5}$. In how many ways can two identical knights be placed on distinct squares of an $8 \times 8$ c...
Two knights placed on distinct squares of an $8 \times 8$ chessboard, where each square is a unit square, are said to attack each other if the distance between the centers of the squares on which the knights lie is $\sqrt{5}$. In how many ways can two identical knights be placed on distinct squares of an $8 \times 8$ c...
1848
dapo_math
10
262
Find the minimum value of $2x^2 + 2y^2 + 5z^2 - 2xy - 4yz - 4x - 2z + 15$ for real numbers $x$, $y$, $z$.
Find the minimum value of $2x^2 + 2y^2 + 5z^2 - 2xy - 4yz - 4x - 2z + 15$ for real numbers $x$, $y$, $z$.
10
dapo_math
18
263
Let $x_1$ and $x_2$ be the roots of the equation $x^2 + 3x + 1 = 0$. Compute \[\left(\frac{x_1}{x_2 + 1}\right)^2 + \left(\frac{x_2}{x_1 + 1}\right)^2\]
Let $x_1$ and $x_2$ be the roots of the equation $x^2 + 3x + 1 = 0$. Compute \[\left(\frac{x_1}{x_2 + 1}\right)^2 + \left(\frac{x_2}{x_1 + 1}\right)^2\]
18
dapo_math
10
264
Oscar buys 13 pencils and 3 erasers for $\$1.00$. A pencil costs more than an eraser, and both items cost a whole number of cents. What is the total cost of one pencil and one eraser in cents?
Oscar buys 13 pencils and 3 erasers for $\$1.00$. A pencil costs more than an eraser, and both items cost a whole number of cents. What is the total cost of one pencil and one eraser in cents?
10
dapo_math
2
265
In \(\triangle ABC\), we have \(AB = 1\) and \(AC = 2\). Side \(\overline{BC}\) and the median from \(A\) to \(\overline{BC}\) have the same length. If the length of \(BC\) is in the form \(\sqrt{k}\), please find the value of \(k\).
In \(\triangle ABC\), we have \(AB = 1\) and \(AC = 2\). Side \(\overline{BC}\) and the median from \(A\) to \(\overline{BC}\) have the same length. If the length of \(BC\) is in the form \(\sqrt{k}\), please find the value of \(k\).
2
dapo_math
7
266
Find the sum of all positive integers $x$ such that $3 \times 2^x = n^2 - 1$ for some positive integer $n$.
Find the sum of all positive integers $x$ such that $3 \times 2^x = n^2 - 1$ for some positive integer $n$.
7
dapo_math
9
267
An $n$-sided regular polygon with side length $1$ is rotated by $\frac{180^\circ}{n}$ about its center. The intersection points of the original polygon and the rotated polygon are the vertices of a $2n$-sided regular polygon with side length $\frac{1-\tan^2 10^\circ}{2}$. What is the value of $n$?
An $n$-sided regular polygon with side length $1$ is rotated by $\frac{180^\circ}{n}$ about its center. The intersection points of the original polygon and the rotated polygon are the vertices of a $2n$-sided regular polygon with side length $\frac{1-\tan^2 10^\circ}{2}$. What is the value of $n$?
9
dapo_math
-14
268
Find the minimum value of \[3x^2 + 12y^2 + 27z^2 - 4xy - 6xz - 12yz - 8y - 24z\]over all real numbers $x,$ $y,$ and $z.$
Find the minimum value of \[3x^2 + 12y^2 + 27z^2 - 4xy - 6xz - 12yz - 8y - 24z\]over all real numbers $x,$ $y,$ and $z.$
-14
dapo_math
1
269
Compute $i^{-100}+i^{-99}+i^{-98}+\cdots+i^{-1}+i^0+i^1+\cdots+i^{99}+i^{100}$.
Compute $i^{-100}+i^{-99}+i^{-98}+\cdots+i^{-1}+i^0+i^1+\cdots+i^{99}+i^{100}$.
1
dapo_math
149
270
For any integer $k \geq 1$, let $p(k)$ be the smallest prime which does not divide $k.$ Define the integer function $X(k)$ to be the product of all primes less than $p(k)$ if $p(k) > 2$, and $X(k) = 1$ if $p(k) = 2.$ Let $\{x_n\}$ be the sequence defined by $x_0 = 1$, and $x_{n+1}X(x_n) = x_n p(x_n)$ for $n \geq 0.$ Fi...
For any integer $k \geq 1$, let $p(k)$ be the smallest prime which does not divide $k.$ Define the integer function $X(k)$ to be the product of all primes less than $p(k)$ if $p(k) > 2$, and $X(k) = 1$ if $p(k) = 2.$ Let $\{x_n\}$ be the sequence defined by $x_0 = 1$, and $x_{n+1}X(x_n) = x_n p(x_n)$ for $n \geq 0.$ Fi...
149
dapo_math
3
271
On an algebra quiz, $10\%$ of the students scored $70$ points, $35\%$ scored $80$ points, $30\%$ scored $90$ points, and the rest scored $100$ points. Find the difference between the mean and median score of the students' scores on this quiz.
On an algebra quiz, $10\%$ of the students scored $70$ points, $35\%$ scored $80$ points, $30\%$ scored $90$ points, and the rest scored $100$ points. Find the difference between the mean and median score of the students' scores on this quiz.
3
dapo_math
544
272
A city is laid out with a rectangular grid of roads with 10 streets numbered from 1 to 10 running east-west and 16 avenues numbered from 1 to 16 running northsouth. All streets end at First and Sixteenth Avenues, and all avenues end at First and Tenth Streets. A rectangular city park is bounded on the north and south...
A city is laid out with a rectangular grid of roads with 10 streets numbered from 1 to 10 running east-west and 16 avenues numbered from 1 to 16 running northsouth. All streets end at First and Sixteenth Avenues, and all avenues end at First and Tenth Streets. A rectangular city park is bounded on the north and south...
544
dapo_math
2695
273
Given a positive integer $n$ with prime factorization $p_1^{e_1}p_2^{e_2}... p_k^{e_k}$ , we define $f(n)$ to be $\sum^k_{i=1}p_ie_i$. In other words, $f(n)$ is the sum of the prime divisors of $n$, counted with multiplicities. Let $M$ be the largest odd integer such that $f(M) = 2023$, and $m$ the smallest odd intege...
Given a positive integer $n$ with prime factorization $p_1^{e_1}p_2^{e_2}... p_k^{e_k}$ , we define $f(n)$ to be $\sum^k_{i=1}p_ie_i$. In other words, $f(n)$ is the sum of the prime divisors of $n$, counted with multiplicities. Let $M$ be the largest odd integer such that $f(M) = 2023$, and $m$ the smallest odd intege...
2695
dapo_math
625
274
In this figure, \( \angle RFS = \angle FDR \), \( FD = 4 \) inches, \( DR = 6 \) inches, \( FR = 5 \) inches, \( FS = 7\frac{1}{2} \) inches. Find the length of \( RS \), in inches, as a decimal. Multiply your final answer by 100 and provide the result.
In this figure, \( \angle RFS = \angle FDR \), \( FD = 4 \) inches, \( DR = 6 \) inches, \( FR = 5 \) inches, \( FS = 7\frac{1}{2} \) inches. Find the length of \( RS \), in inches, as a decimal. Multiply your final answer by 100 and provide the result.
625
dapo_math
14
275
The sides and vertices of a pentagon are labeled with the numbers $1$ through $10$. Each side of the pentagon must have the same sum of numbers. What is the smallest possible value of this sum?
The sides and vertices of a pentagon are labeled with the numbers $1$ through $10$. Each side of the pentagon must have the same sum of numbers. What is the smallest possible value of this sum?
14
dapo_math
504
276
The Venusian prophet Zabruberson sent his pupils a $10000$-letter word, with each letter being either $A$ or $E$. This is known as the Zabrubic word. The pupils consider that for $1 \leq k \leq 10000$, each word comprised of $k$ consecutive letters of the Zabrubic word is a prophetic word of length $k$. It is known tha...
The Venusian prophet Zabruberson sent his pupils a $10000$-letter word, with each letter being either $A$ or $E$. This is known as the Zabrubic word. The pupils consider that for $1 \leq k \leq 10000$, each word comprised of $k$ consecutive letters of the Zabrubic word is a prophetic word of length $k$. It is known tha...
504
dapo_math
30
277
Two farmers agree that pigs are worth $300$ dollars and that goats are worth $210$ dollars. When one farmer owes the other money, he pays the debt in pigs or goats, with "change" received in the form of goats or pigs as necessary. (For example, a $390$ dollar debt could be paid with two pigs, with one goat received in ...
Two farmers agree that pigs are worth $300$ dollars and that goats are worth $210$ dollars. When one farmer owes the other money, he pays the debt in pigs or goats, with "change" received in the form of goats or pigs as necessary. (For example, a $390$ dollar debt could be paid with two pigs, with one goat received in ...
30
dapo_math
30
278
Suppose $\cos Q = 0.4$ in the diagram below. What is $QR$? [asy] pair P,Q,R; P = (0,0); Q = (6,0); R = (0,6*tan(acos(0.4))); draw(P--Q--R--P); draw(rightanglemark(Q,P,R,18)); label("$P$",P,SW); label("$Q$",Q,SE); label("$R$",R,N); label("$12$",Q/2,S); [/asy]
Suppose $\cos Q = 0.4$ in the diagram below. What is $QR$? [asy] pair P,Q,R; P = (0,0); Q = (6,0); R = (0,6*tan(acos(0.4))); draw(P--Q--R--P); draw(rightanglemark(Q,P,R,18)); label("$P$",P,SW); label("$Q$",Q,SE); label("$R$",R,N); label("$12$",Q/2,S); [/asy]
30
dapo_math
47
279
Points $A$ and $B$ are the endpoints of a diameter of a circle with center $C$. Points $D$ and $E$ lie on the same diameter such that $C$ bisects segment $\overline{DE}$. Let $F$ be a randomly chosen point within the circle. The probability that $\triangle DEF$ has a perimeter less than the length of the diameter of th...
Points $A$ and $B$ are the endpoints of a diameter of a circle with center $C$. Points $D$ and $E$ lie on the same diameter such that $C$ bisects segment $\overline{DE}$. Let $F$ be a randomly chosen point within the circle. The probability that $\triangle DEF$ has a perimeter less than the length of the diameter of th...
47
dapo_math
33
280
In rectangle $ABCD$, point $M$ is the midpoint of $AB$, and $P$ is a point on side $BC$. The perpendicular bisector of $MP$ intersects side $DA$ at point $X$. Given that $AB = 33$ and $BC = 56$, find the least possible value of $MX$.
In rectangle $ABCD$, point $M$ is the midpoint of $AB$, and $P$ is a point on side $BC$. The perpendicular bisector of $MP$ intersects side $DA$ at point $X$. Given that $AB = 33$ and $BC = 56$, find the least possible value of $MX$.
33
dapo_math
4
281
Find the largest $n$ for which there exists a sequence $(a_0, a_1, \ldots, a_n)$ of non-zero digits such that, for each $k$, $1 \le k \le n$, the $k$-digit number $\overline{a_{k-1} a_{k-2} \ldots a_0} = a_{k-1} 10^{k-1} + a_{k-2} 10^{k-2} + \cdots + a_0$ divides the $(k+1)$-digit number $\overline{a_{k} a_{k-1}a_{k-2}...
Find the largest $n$ for which there exists a sequence $(a_0, a_1, \ldots, a_n)$ of non-zero digits such that, for each $k$, $1 \le k \le n$, the $k$-digit number $\overline{a_{k-1} a_{k-2} \ldots a_0} = a_{k-1} 10^{k-1} + a_{k-2} 10^{k-2} + \cdots + a_0$ divides the $(k+1)$-digit number $\overline{a_{k} a_{k-1}a_{k-2}...
4
dapo_math
850
282
Let $P(x) = x^2 - 3x - 9$. A real number $x$ is chosen at random from the interval $5 \le x \le 15$. The probability that $\lfloor\sqrt{P(x)}\rfloor = \sqrt{P(\lfloor x \rfloor)}$ is equal to $\frac{\sqrt{a} + \sqrt{b} + \sqrt{c} - d}{e}$ , where $a$, $b$, $c$, $d$, and $e$ are positive integers. Find $a + b + c + d + ...
Let $P(x) = x^2 - 3x - 9$. A real number $x$ is chosen at random from the interval $5 \le x \le 15$. The probability that $\lfloor\sqrt{P(x)}\rfloor = \sqrt{P(\lfloor x \rfloor)}$ is equal to $\frac{\sqrt{a} + \sqrt{b} + \sqrt{c} - d}{e}$ , where $a$, $b$, $c$, $d$, and $e$ are positive integers. Find $a + b + c + d + ...
850
dapo_math
61
283
Natasha has more than $\$1$ but less than $\$10$ worth of dimes. When she puts her dimes in stacks of 3, she has 1 left over. When she puts them in stacks of 4, she has 1 left over. When she puts them in stacks of 5, she also has 1 left over. How many dimes does Natasha have?
Natasha has more than $\$1$ but less than $\$10$ worth of dimes. When she puts her dimes in stacks of 3, she has 1 left over. When she puts them in stacks of 4, she has 1 left over. When she puts them in stacks of 5, she also has 1 left over. How many dimes does Natasha have?
61
dapo_math
875
284
Find the last three digits in the product $1 \cdot 3 \cdot 5 \cdot 7 \cdot \ldots \cdot 2009 \cdot 2011$.
Find the last three digits in the product $1 \cdot 3 \cdot 5 \cdot 7 \cdot \ldots \cdot 2009 \cdot 2011$.
875
dapo_math
2
285
Two strips of width 1 overlap at an angle of \(\alpha\) as shown. Find the area of the overlap (shown shaded) in terms of \(\alpha\). The answer is in the form \(\frac{k}{m}\), where \(k\) and \(m\) are integers. Please provide the value of \(k + m\).
Two strips of width 1 overlap at an angle of \(\alpha\) as shown. Find the area of the overlap (shown shaded) in terms of \(\alpha\). The answer is in the form \(\frac{k}{m}\), where \(k\) and \(m\) are integers. Please provide the value of \(k + m\).
2
dapo_math
419
286
Find the largest integer $x<1000$ such that $\left(\begin{array}{c}1515 \\ x\end{array}\right)$ and $\left(\begin{array}{c}1975 \\ x\end{array}\right)$ are both odd.
Find the largest integer $x<1000$ such that $\left(\begin{array}{c}1515 \\ x\end{array}\right)$ and $\left(\begin{array}{c}1975 \\ x\end{array}\right)$ are both odd.
419
dapo_math
400
287
Suppose that the angles of triangle $ABC$ satisfy \[\cos 3A + \cos 3B + \cos 3C = 1.\]Two sides of the triangle have lengths 10 and 13. Find the maximum length of the third side.The answer is in the form k\sqrt{m}+n,. Please provide the value of k + m + n.
Suppose that the angles of triangle $ABC$ satisfy \[\cos 3A + \cos 3B + \cos 3C = 1.\]Two sides of the triangle have lengths 10 and 13. Find the maximum length of the third side.The answer is in the form k\sqrt{m}+n,. Please provide the value of k + m + n.
400
dapo_math
1260
288
A child builds towers using identically shaped cubes of different colors. How many different towers with a height of $8$ cubes can the child build using $2$ red cubes, $3$ blue cubes, and $4$ green cubes? (One cube will be left out.) Please provide your answer as an integer.
A child builds towers using identically shaped cubes of different colors. How many different towers with a height of $8$ cubes can the child build using $2$ red cubes, $3$ blue cubes, and $4$ green cubes? (One cube will be left out.) Please provide your answer as an integer.
1260
dapo_math
572
289
已知多项式 $$ f(z)=z^{3}+a z^{2}+b z+c(a, b. c \in \mathbf{Z}) $$ 的所有根的模都是 20 或 15. 则这样的多 项式有 $\qquad$个。
已知多项式 $$ f(z)=z^{3}+a z^{2}+b z+c(a, b. c \in \mathbf{Z}) $$ 的所有根的模都是 20 或 15. 则这样的多 项式有 $\qquad$个。
572
dapo_math
10
290
已知整数 $a, b, c, d$ 满足 $a+b+c+d=6$ ,则 $a b+a c+a d+b c+b d+c d$ 的正整数取值个数为 $\qquad$.
已知整数 $a, b, c, d$ 满足 $a+b+c+d=6$ ,则 $a b+a c+a d+b c+b d+c d$ 的正整数取值个数为 $\qquad$.
10
dapo_math
8
291
In the diagram, $AB,$ $BC,$ $CD,$ $DE,$ $EF,$ $FG,$ $GH,$ and $HK$ all have length $4,$ and all angles are right angles, with the exception of the angles at $D$ and $F.$ [asy] draw((0,0)--(0,4)--(4,4)--(4,8)--(6.8284,5.1716)--(9.6569,8)--(9.6569,4)--(13.6569,4)--(13.6569,0)--cycle,black+linewidth(1)); draw((0,0)--(0.5...
In the diagram, $AB,$ $BC,$ $CD,$ $DE,$ $EF,$ $FG,$ $GH,$ and $HK$ all have length $4,$ and all angles are right angles, with the exception of the angles at $D$ and $F.$ [asy] draw((0,0)--(0,4)--(4,4)--(4,8)--(6.8284,5.1716)--(9.6569,8)--(9.6569,4)--(13.6569,4)--(13.6569,0)--cycle,black+linewidth(1)); draw((0,0)--(0.5...
8
dapo_math
45
292
Square $ABCD$ is divided into four rectangles by lines $EF$ and $GH$. Line $EF$ is parallel to $AB$, and line $GH$ is parallel to $BC$. It is given that $\angle BAF = 18^\circ$. The lines $EF$ and $GH$ intersect at point $P$. The area of rectangle $PFCH$ is twice that of rectangle $AGPE$. Given that the value of $\angl...
Square $ABCD$ is divided into four rectangles by lines $EF$ and $GH$. Line $EF$ is parallel to $AB$, and line $GH$ is parallel to $BC$. It is given that $\angle BAF = 18^\circ$. The lines $EF$ and $GH$ intersect at point $P$. The area of rectangle $PFCH$ is twice that of rectangle $AGPE$. Given that the value of $\angl...
45
dapo_math
98
293
In a trapezoid $ABCD$ with $AB$ parallel to $CD$, the diagonals $AC$ and $BD$ intersect at $E$. If the area of triangle $ABE$ is 50 square units, and the area of triangle $ADE$ is 20 square units, what is the area of trapezoid $ABCD$?
In a trapezoid $ABCD$ with $AB$ parallel to $CD$, the diagonals $AC$ and $BD$ intersect at $E$. If the area of triangle $ABE$ is 50 square units, and the area of triangle $ADE$ is 20 square units, what is the area of trapezoid $ABCD$?
98
dapo_math
24
294
某班有 47 个学生,所用教室有 6 排,每排有 8个座位,用 $(i, j)$ 表示位于第 $i$ 排第 $j$ 列的座位。新学期准备调整座位,设某学生原来的座位为 $(i, j)$ ,如果调整后的座位为 $(m, n)$ ,则称该生作了移动 $[a$, $b]=[i-m, j-n]$ ,并称 $a+b$ 为该生的位置数。所有学生的位置数之和记为 $S$ 。求 $S$ 的最大可能值与最小可能值之差。
某班有 47 个学生,所用教室有 6 排,每排有 8个座位,用 $(i, j)$ 表示位于第 $i$ 排第 $j$ 列的座位。新学期准备调整座位,设某学生原来的座位为 $(i, j)$ ,如果调整后的座位为 $(m, n)$ ,则称该生作了移动 $[a$, $b]=[i-m, j-n]$ ,并称 $a+b$ 为该生的位置数。所有学生的位置数之和记为 $S$ 。求 $S$ 的最大可能值与最小可能值之差。
24
dapo_math
60
295
Convex pentagon $ABCDE$ has side lengths $AB=5$, $BC=CD=DE=6$, and $EA=7$. Moreover, the pentagon has an inscribed circle (a circle tangent to each side of the pentagon). Find the area of $ABCDE$.
Convex pentagon $ABCDE$ has side lengths $AB=5$, $BC=CD=DE=6$, and $EA=7$. Moreover, the pentagon has an inscribed circle (a circle tangent to each side of the pentagon). Find the area of $ABCDE$.
60
dapo_math
0
296
复数 $z_{1}, z_{2}, \\cdots, z_{100}$ 满足: $z_{1}=3+2 \\mathrm{i}, z_{n+1}=\\overline{z_{n}} \\cdot \\mathrm{i}^{n}(n=1,2, \\cdots, 99)$ ( i 为虚数单位), 请给出 $z_{99}+z_{100}$ 的实部和虚部之和。
复数 $z_{1}, z_{2}, \\cdots, z_{100}$ 满足: $z_{1}=3+2 \\mathrm{i}, z_{n+1}=\\overline{z_{n}} \\cdot \\mathrm{i}^{n}(n=1,2, \\cdots, 99)$ ( i 为虚数单位), 请给出 $z_{99}+z_{100}$ 的实部和虚部之和。
0
dapo_math
10
297
Find the sum of all positive integers $x$ such that $|x^2-x-6|$ has exactly 4 positive integer divisors.
Find the sum of all positive integers $x$ such that $|x^2-x-6|$ has exactly 4 positive integer divisors.
10
dapo_math
142
298
For how many integer values of $n$ between 1 and 1000 inclusive does the decimal representation of $\frac{n}{1400}$ terminate?
For how many integer values of $n$ between 1 and 1000 inclusive does the decimal representation of $\frac{n}{1400}$ terminate?
142
dapo_math
6
299
Find the first digit after the decimal point of the number $\displaystyle \frac{1}{1009} + \frac{1}{1010} + \cdots + \frac{1}{2016}$.
Find the first digit after the decimal point of the number $\displaystyle \frac{1}{1009} + \frac{1}{1010} + \cdots + \frac{1}{2016}$.
6
dapo_math
5
300
已知 $a x^{3}+b x^{2}+x+1=0(a<0)$ 恰有两个零点, 求 $a+b$ 的取值范围。标准答案格式为$\left(-\infty, \frac{a}{b}\right)$,请给出区间端点a+b的和。
已知 $a x^{3}+b x^{2}+x+1=0(a<0)$ 恰有两个零点, 求 $a+b$ 的取值范围。标准答案格式为$\left(-\infty, \frac{a}{b}\right)$,请给出区间端点a+b的和。
5
dapo_math