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int64
5
895
Let the function $f(x)= \frac {3}{2}x^{2}-2ax$ ($a > 0$) and $g(x)=a^{2}\ln x+b$ have a common point, and the equations of tangent lines at the common point are the same. Find the maximum value of the real number $b$.
b= \frac {1}{2e^{2}}
math
71
Given the parabola $y=ax^2$ passes through point A(1, 2), then $a= \_\_\_\_\_\_$, and the equation of the directrix is $\_\_\_\_\_\_$.
a=2; y=-\frac{1}{8}
math
49
Consider the quadratic equation $5x^2 - 6x - 12 = 0$. The positive difference between the two roots of this equation can be written as $\frac{\sqrt{p}}{q}$, where $q$ is an integer and $p$ is an integer not divisible by the square of any prime number. Find $p + q$.
74
math
76
Let $S = \{1, 22, 333, \dots , 999999999\}$ . For how many pairs of integers $(a, b)$ where $a, b \in S$ and $a < b$ is it the case that $a$ divides $b$ ?
14
math
82
Given vectors $\overrightarrow{a}=(-2,-1,3)$, $\overrightarrow{b}=(-1,1,2)$, $\overrightarrow{c}=(x,2,2)$. $(1)$ When $|\overrightarrow{c}|=2\sqrt{2}$, if the vector $k\overrightarrow{a}+\overrightarrow{b}$ is perpendicular to $\overrightarrow{c}$, find the values of the real numbers $x$ and $k$. $(2)$ If the vecto...
x=-\frac{4}{5}
math
149
Given that the shortest distance from a point on the circle $(x-2)^2+y^2=1$ to the line $y= \sqrt {3}x+b$ is $\sqrt {3}$, find the value of $b$.
2
math
51
For which integers \( n \geq 3 \) does there exist a regular \( n \)-gon in the plane such that all its vertices have integer coordinates in a rectangular coordinate system?
4
math
39
Let the complex number \(z\) satisfy \(z=\dfrac{-1+i}{1+i}\), calculate the modulus of \(z\).
1
math
29
For the elective course "Coordinate System and Parametric Equations," determine the length of the chord cut by the line $$ \begin{cases} x=1+4t, \\ y=-1-3t \end{cases} \quad (t \text{ is a parameter}) $$ from the curve $$ \rho = \sqrt{2}\cos\left(\theta + \frac{\pi}{4}\right). $$
\frac{7}{5}
math
95
$|5x^2-\tfrac25|\le|x-8|$ if and only if $x$ is in the interval $[a, b]$ . There are relatively prime positive integers $m$ and $n$ so that $b -a =\tfrac{m}{n}$ . Find $m + n$ .
18
math
82
**Text**: The function $f(x)$ is an even function defined on $\mathbb{R}$, and its graph is symmetric about the line $x = 2$. When $x \in (-2,2)$, $f(x) = -x^2 + 1$. Then, when $x \in (-4, -2)$, the expression for $f(x)$ is __________.
-(x + 4)^2 + 1
math
85
A sphere intersects the $xy$-plane in a circle centered at $(3,5,0)$ with a radius of 2. The sphere also intersects the $yz$-plane in a circle centered at $(0,5,-8),$ with radius $r.$ Find $r.$
\sqrt{59}
math
59
Given a hyperbola $\frac{x^2}{a^2} - \frac{y^2}{b^2} = 1$ (where $a > 0, b > 0$), with one of its foci at F$(c, 0)$, and one endpoint of the imaginary axis at B$(0, b)$. If the line FB is perpendicular to the asymptote $y = \frac{b}{a}x$ of the hyperbola, find the eccentricity of this hyperbola.
e = \frac{1 + \sqrt{5}}{2}
math
113
Given the function $f(x) = 4x^2 - 4ax + a^2 - 2a + 2$ has a maximum value of 3 on the interval $[0, 2]$. Find the value of the real number $a$.
1 + \sqrt{2}
math
57
Consider the sequence whose nth term is $(-1)^n\cdot (n+1)$. Calculate the average of the first 150 terms of this sequence.
-0.5
math
35
In the arithmetic sequence {a<sub>n</sub>}, a<sub>3</sub>+a<sub>4</sub>+a<sub>5</sub>=84, a<sub>9</sub>=73. (I) Find the general term formula for the sequence {a<sub>n</sub>}; (II) For any m∈N*, let b<sub>m</sub> denote the number of terms in the sequence {a<sub>n</sub>} that fall within the interval (9<sup>m</sup>,9<s...
S_{m}=\frac {9^{2m+1}-10×9^{m}+1}{80}
math
152
How long are the midlines of a triangle if the sides of the triangle are given?
s_{a} = \frac{1}{2} b, \quad s_{b} = \frac{1}{2} c, \quad s_{c} = \frac{1}{2} a
math
18
(1) Find the coefficient of $x^3$ in the expansion of $(\frac{1}{2} - x)^5$ and the sum of all coefficients in the expansion. (2) From the numbers 0, 2, 3, 4, 5, 6, select any 4 to form a 4-digit number without repeating digits. Find the number of 4-digit numbers that meet the condition.
300
math
91
Given the sequence $\{a_n\}$ where the sum of the first $n$ terms $S_n=n^2+1$, and the sequence $\{b_n\}$ where $b_n=\frac{2}{a_n+1}$, find the value of $b_5$.
\frac{1}{5}
math
61
Given the expression \( \left(1-\frac{1}{2^{2}}\right)\left(1-\frac{1}{3^{2}}\right)\ldots\left(1-\frac{1}{12^{2}}\right) \), compute its value.
\frac{13}{24}
math
60
In $\triangle ABC$, the sides opposite to angles $A$, $B$, and $C$ are $a$, $b$, and $c$ respectively. Given $a=2$, $3b\sin C-5c\sin B\cos A=0$, find the maximum area of $\triangle ABC$.
2
math
66
In triangle $ABC$, let $a$, $b$, and $c$ be the lengths of the sides opposite to angles $A$, $B$, and $C$, respectively. Given that $a\cos B = 4$ and $b\sin A = 3$. (I) Find $\tan B$ and the value of side $a$; (II) If the area of triangle $ABC$ is $S = 9$, find the perimeter of triangle $ABC$.
11 + \sqrt{13}
math
101
Let \( n \in \mathbf{Z}_{+} \). When \( n > 100 \), the first two digits of the decimal part of \( \sqrt{n^{2}+3n+1} \) are ______.
50
math
52
If $\tan{\alpha}$ and $\tan{\beta}$ are the roots of $x^2 - 3px + 4q = 0$, and $\tan{\alpha} \cdot \tan{\beta}$ is the value of $s$ in the equation $x^2 - 7rx + s = 0$ where $\cot{\alpha} + \cot{\beta} = r$, determine the value of $rs$.
3p
math
91
What is the increasing interval of the function $y=\sin (-2x+ \frac{\pi}{4})$?
\left[k\pi+ \frac{3}{8}\pi,k\pi+ \frac{7}{8}\pi\right]
math
25
Given proposition p: The function $y=x^2-3ax+4$ is increasing on the interval $[1, +\infty)$, and proposition q: The function $y=(2a-1)^x$ is a decreasing function. If "p and q" is a false proposition, determine the range of values for the real number $a$.
(-\infty, \frac{1}{2}] \cup (\frac{2}{3}, +\infty)
math
76
At a conference, the 2016 participants were registered from P1 to P2016. Each participant from P1 to P2015 shook hands with exactly the same number of participants as the number on their registration form. How many hands did the 2016th participant shake?
1008
math
65
In triangle \(ABC\) with the ratio of the sides \(AB: AC = 5: 2\), the angle bisector of \(\angle BAC\) intersects side \(BC\) at point \(L\). Find the length of segment \(AL\) if the length of the vector \(2 \cdot \overrightarrow{AB} + 5 \cdot \overrightarrow{AC}\) is 2016.
288
math
88
Evaluate the value of $\frac{(2210-2137)^2 + (2137-2028)^2}{64}$.
268.90625
math
36
For the cubic function $f(x) = ax^3 + bx^2 + cx + d$ ($a \neq 0$), a definition is given: Let $f'(x)$ be the derivative of the function $y = f(x)$, and $f''(x)$ the derivative of $f'(x)$. If the equation $f''(x) = 0$ has real solutions $x_0$, then the point $(x_0, f(x_0))$ is called the "inflection point" of the functi...
2012
math
288
The points $P(3,-2), Q(3,1), R(7,1)$, and $S$ form a rectangle. What are the coordinates of $S$?
(7,-2)
math
39
There are exactly 120 ways to color five cells in a $5 \times 5$ grid such that exactly one cell in each row and each column is colored. There are exactly 96 ways to color five cells in a $5 \times 5$ grid without the corner cell, such that exactly one cell in each row and each column is colored. How many ways are th...
78
math
114
Given a positive integer $n$ not exceeding $100$ such that if $n \leq 60$, the probability of choosing $n$ is $p$, and if $n > 60$, the probability of choosing $n$ is $2p$. Find the probability that a randomly chosen integer is a perfect square.
\frac{3}{35}
math
71
The graphs of $y = -|x-a|^2 + b$ and $y = |x-c|^2 + d$ intersect at points $(1,8)$ and $(9,4)$. Find $a+c$.
10
math
47
Convert 89 to binary.
1011001_{(2)}
math
7
Let x and y be two-digit positive integers with a mean of 45. Find the maximum value of the ratio x/y.
8
math
27
Determine the number of whole number values for the cost $x$ of each ticket, such that the total cost of tickets for the 9th graders is $60, the total cost of tickets for the 10th graders is $90, and the total cost of tickets for the 11th graders is $49$.
1
math
74
Given the function f(x) = -x^3 - 6x^2 - 9x + 3. (I) Find the interval(s) where the function is strictly decreasing. (II) Find the maximum and minimum values of the function on the interval [-4, 2].
7
math
60
Mario is once again on a quest to save Princess Peach. Mario enters Peach's castle and finds himself in a room with 4 doors. This room is the first in a sequence of 2 indistinguishable rooms. In each room, 1 door leads to the next room in the sequence (or, for the second room, into Bowser's level), while the other 3 do...
20
math
132
Given that the sequence $\{a_n\}$ is an arithmetic sequence with a non-zero common difference, $a_1+1$, $a_2+1$, $a_4+1$ form a geometric sequence, and $a_2+a_3=-12$, then $a_n=$ ______.
-2n-1
math
66
Given the ellipse C: $$\frac {x^{2}}{a^{2}}+ \frac {y^{2}}{b^{2}}=1(a>b>0)$$, with the right focus $$F( \sqrt {3},0)$$, and eccentricity $$e= \frac { \sqrt {3}}{2}$$. (1) Find the equation of ellipse C. (2) A line l passing through F and having an inclination angle of 45° intersects the ellipse at two distinct points M...
\frac {2 \sqrt {6}}{5}
math
131
Given a tetrahedron P-ABC, where PA = 4, AB = AC = $2\sqrt{3}$, BC = 6, and PA is perpendicular to plane ABC, the radius of the circumscribed sphere of this tetrahedron is __________.
4
math
59
During a flood control emergency, a large gasoline canister drifting downstream is to be detonated using a shooting method. It is known that there are only 5 bullets available, and the first successful shot can only cause gasoline to leak, while a second successful hit is required for detonation. The probability of hit...
\frac{232}{243}
math
96
Calculate the value of the polynomial $f(x) = x^{6} - 12x^{5} + 60x^{4} - 160x^{3} + 240x^{2} - 192x + 64$ using Horner's Rule when $x = 2$. Find the value of $v_{4}$.
80
math
82
What is the base ten equivalent of $45327_8$?
19159
math
17
For some positive integer $j$, when 75 is divided by $j^2$, the remainder is 3. What is the remainder when 130 is divided by $j$?
1
math
41
The product of two consecutive page numbers is $20{,}412$. What is the sum of these two page numbers?
285
math
28
How many sets of integers \( (a, b, c, d) \) satisfy: \[ 0 < a < b < c < d < 500, \] \[ a + d = b + c, \] and \[ bc - ad = 93? \] (The 11th USA Mathematical Talent Search, 1993)
405 + 465 = 870
math
78
Find four positive integers such that, when adding them three at a time, the sums are 6, 7, 8, and 9.
1, 2, 3, 4
math
31
In a geometric sequence $\{a_n\}$, it is known that $S_6=48$ and $S_{12}=60$. Find the value of $S_{24}$.
\frac{255}{4}
math
44
Given that $\lg 2 = 0.3010$, determine the number of digits in the integer $2^{2015}$.
607
math
32
Given that the password is a four-digit number composed of one 2, one 9, and two 6s, calculate the maximum number of attempts needed to find the document password.
12
math
38
How many times should two dice be rolled so that the probability of getting two sixes at least once is greater than $1/2$?
25
math
30
Solve the following equation in the set of real numbers: $$ 1+2 \sqrt{x}-\sqrt[3]{x}-2 \sqrt[6]{x}=0 $$
x = 1 \quad \text{and} \quad x = \frac{1}{64}
math
39
Rationalize the denominator of \(\frac{35}{\sqrt[3]{35}}\).
\sqrt[3]{1225}
math
23
In trapezoid \(ABCD\), a point \(X\) is taken on the base \(AD\) such that segments \(XB\) and \(XC\) divide the trapezoid into three similar, yet pairwise unequal, non-isosceles triangles. The side \(AB\) has a length of 6. Find \(AX \cdot DX\).
36
math
74
The function $f(x) = \cos x$ is transformed such that the abscissa of each point on the graph becomes $\frac{1}{\omega}$ times the original ($\omega > 0$), while the ordinate remains unchanged. The resulting graph is then shifted to the right by $\frac{\pi}{12}$ units. The new graph is symmetric about the line $x = \fr...
\omega = 6
math
99
Given the universal set $U=\mathbb{R}$, set $A=\{x\mid y=\frac{1}{\sqrt{a-x}}\}$, and set $B=\{x\mid x^2-x-6=0\}$. 1. If $a=-1$, find $A\cap B$. 2. If $(\neg_{U}A)\cap B=\varnothing$, find the range of values for the real number $a$.
a\in(3,+\infty)
math
101
Given the sequence: $$( \frac{1}{1}), ( \frac{1}{2}, \frac{2}{1}), ( \frac{1}{3}, \frac{2}{2}, \frac{3}{1}), ( \frac{1}{4}, \frac{2}{3}, \frac{3}{2}, \frac{4}{1}), \ldots, ( \frac{1}{n}, \frac{2}{n-1}, \frac{3}{n-2}, \ldots, \frac{n-1}{2}, \frac{n}{1})$$, denote the elements of the sequence as: $a_1, a_2, a_3, a_4, a_5...
7
math
178
A boy buys oranges at the rate of 4 oranges for 15 cents and sells them at the rate of 6 oranges for 30 cents. Calculate the number of oranges he needs to sell to make a profit of 200 cents.
160
math
52
Find the smallest natural number \( n \) for which \( 1999! \) is not divisible by \( 34^n \).
124
math
31
(1) Use the Euclidean algorithm to find the greatest common divisor (GCD) of 117 and 182, and verify it using the method of successive subtraction. (2) Use the Horner's method to calculate the value of the polynomial \\(f(x)=1-9x+8x^{2}-4x^{4}+5x^{5}+3x^{6}\\) at \\(x=-1\\).
12
math
97
In multiplying two positive integers $a$ and $b$, Ron reversed the digits of the two-digit number $a$. His erroneous product was $161$. What is the correct value of the product of $a$ and $b$?
224
math
50
In a certain school, there are 5000 students. Each student is assigned an ID number from 0001 to 5000. No two students can have the same ID number. If a student is selected uniformly at random, what is the probability that the ID number of the student does not contain any 2s among its digits?
\frac{729}{1250}
math
75
Given the constant $a > 1$ and real numbers $x$ and $y$ that satisfy the equation $\log_{a}x + 2\log_{x}a + \log_{x}y = -3$, if the maximum value of $y$ is $\sqrt{2}$, find the value of $x$.
x = \frac{1}{8}
math
71
What is the coefficient of $x^2$ when $-5x^3 - 5x^2 - 7x + 1$ is multiplied by $-x^2 - 6x + 1$ and the like terms are combined?
36
math
54
Let $a$ and $b$ be real numbers. Consider the following five statements: 1. $a < b$ 2. $b < 0$ 3. $a < 0$ 4. $\frac{1}{a} < \frac{1}{b}$ 5. $a^2 < b^2$ What is the maximum number of these statements that can be true for any values of $a$ and $b$?
3
math
94
For $ n \equal{} 1,\ 2,\ 3,\ \cdots$ , let $ (p_n,\ q_n)\ (p_n > 0,\ q_n > 0)$ be the point of intersection of $ y \equal{} \ln (nx)$ and $ \left(x \minus{} \frac {1}{n}\right)^2 \plus{} y^2 \equal{} 1$ . (1) Show that $ 1 \minus{} q_n^2\leq \frac {(e \minus{} 1)^2}{n^2}$ to find $ \lim_{n\to\infty} q_n$ . ...
1
math
190
Yura was walking along the road and met a tractor pulling a long pipe. Yura decided to measure the length of the pipe. He walked along it "against the movement of the tractor" and counted 20 steps. Then he walked along the pipe "with the movement of the tractor" and counted 140 steps. Knowing that his step is 1 meter, ...
35
math
105
Calculate the sum $$\frac{2^1}{8^1 - 1} + \frac{2^2}{8^2 - 1} + \frac{2^3}{8^3 - 1} + \frac{2^4}{8^4 - 1} + \cdots.$$
\frac{1}{3}
math
68
Solve the system of equations: \[ \begin{cases} x - y + z = 1 \\ y - z + u = 2 \\ z - u + v = 3 \\ u - v + x = 4 \\ v - x + y = 5 \end{cases} \]
(0,6,7,3,-1)
math
66
In the xy-plane, what is the length of the shortest path from $(0,0)$ to $(15,20)$ that does not go inside the circle $(x-9)^{2}+(y-12)^{2}= 36$? A) $6\sqrt{21} + \pi$ B) $3\sqrt{21} + 2\pi$ C) $6\sqrt{21} + 2\pi$ D) $12 + 4\pi$ E) $9\sqrt{21} + \pi$
6\sqrt{21} + 2\pi
math
127
Given points $(-3,{y}_{1}),(1,{y}_{2}),(-\frac{1}{2},{y}_{3})$ are all on the graph of the function $y=x^{2}-2x+3$, compare the values of $y_1, y_2$, and $y_3$.
y_{2} < y_{3} < y_{1}
math
68
What is the value of $0.\overline{234} + 0.\overline{567} - 0.\overline{891}$? Express your answer as a fraction in lowest terms.
\frac{-10}{111}
math
48
When Tanya excluded all numbers from 1 to 333 that are divisible by 3 but not by 7, and all numbers that are divisible by 7 but not by 3, she ended up with 215 numbers. Did she solve the problem correctly?
205
math
58
If the sequence $\{a_{n}\}$ is a sequence of positive terms, and $\sqrt{{a_1}}+\sqrt{{a_2}}+⋯+\sqrt{{a_n}}={n^2}+3n(n\in N^{*})$, then $a_{2}=$______,$\frac{{{a_1}}}{2}+\frac{{{a_2}}}{3}+⋯+\frac{{{a_n}}}{{n+1}}=\_\_\_\_\_\_.$
2n^{2}+6n
math
107
Find the point where the line passing through $(2, -1, 3)$ and $(6, -5, 7)$ intersects the $xz$-plane.
(1, 0, 2)
math
35
Given that the slant height of a cone is 2, and its net is a semicircle, what is the area of the cross section of the axis of the cone?
\sqrt{3}
math
37
In the rectangular coordinate system $xoy$, the parametric equations of circle $C$ are given by $\begin{cases}x=1+\cos φ \\\\ y=\sin φ\end{cases}$ ($φ$ is the parameter). Establish a polar coordinate system with $O$ as the pole and the non-negative half of the $x$-axis as the polar axis. (1) Find the Cartesian equatio...
2 \sqrt{3}
math
192
Let $z$ be a complex number such that \[z^3 + \frac{1}{z^3} = 52.\]Find all possible values of \[z + \frac{1}{z}.\]Enter all possible values, separated by commas.
4, -2 + 3i, -2 - 3i
math
58
Given that ${F_1}$ and ${F_2}$ are the left and right foci of the ellipse $\frac{x^2}{a^2} + \frac{y^2}{b^2} = 1 (a > b > 0)$, respectively. $A$ and $B$ are the right and upper vertices of the ellipse, respectively. $P$ is a point on the ellipse, $O$ is the coordinate origin, $OP$ is parallel to $AB$, $PF_1$ is perpend...
\frac{x^2}{10} + \frac{y^2}{5} = 1
math
147
Given $a_{n}=2n-1$, $b_{n}=\left\{\begin{array}{l}{2{a}_{n},n\text{ is even}}\\{-{a}_{n},n\text{ is odd}}\end{array}\right.$, determine the formula for $S_{2n}$.
2n^2+3n
math
72
Given that the function $f(x-1)$ is an odd function, and the function $f(x+3)$ is an even function, with $f(0)=1$, then $f(8)=$ ?
-1
math
45
A right triangle with integer leg lengths is called "cool'' if the number of square units in its area is equal to twice the number of units in the sum of the lengths of its legs. What is the sum of all the different possible areas of cool right triangles?
118
math
54
The equation of the tangent line to the function \(y = xe^x\) at the point \((1, e)\) is \(y = xe^x \) is tangent to \(y = x - 1 + e\) at the point \((x, y)\), determine the general equation of the tangent line.
y = 2ex - e
math
67
Given that \\(f(x)\\) is an odd function, and when \\(x < 0\\), \\(f(x) = x^{4} - x\\), then the equation of the tangent line to the curve \\(y = f(x)\\) at \\(x = 1\\) is \_\_\_\_\_\_.
5x + y - 3 = 0
math
74
Given the quadratic function $f\left(x\right)=ax^{2}+bx+c$ passes through the point $\left(0,3\right)$, and the solution set of the inequality $ax^{2}+bx+c\leqslant 0$ is $\{x\left|\right.1\leqslant x\leqslant 3\}$. $(1)$ Find the analytical expression of $f\left(x\right)$; $(2)$ If $g\left(x\right)=f\left(x\right)...
\lambda \in \left(\frac{2}{3}, +\infty \right)
math
223
A rectangular parallelepiped with dimensions \( m \times n \times k \) is divided into unit cubes. How many parallelepipeds in total (including the original one) are formed?
\frac{m n k (m+1)(n+1)(k+1)}{8}
math
40
Given \(| \overrightarrow{a}|=3 \sqrt {2}\) and \(| \overrightarrow{b}|=6\), and \(\overrightarrow{a}+ \overrightarrow{b}\) is perpendicular to \(\overrightarrow{a}\), find the angle between \(\overrightarrow{a}\) and \(\overrightarrow{b}\).
135^{\circ}
math
78
The length, width, and height of a certain rectangular prism are $4$, $2$, and $1$ respectively, calculate the surface area of the circumscribed sphere of the rectangular prism.
21\pi
math
40
Given that the sequence $\{a\_n\}$ is an arithmetic sequence, $a\_1+a\_5=-20$, $a\_3+a\_8=-10$. 1. Find the general term of the sequence $\{a\_n\}$. 2. For what value of $n$ does the sum of the first $n$ terms of the sequence $\{a\_n\}$, denoted as $S\_n$, reach its minimum? Also, find this minimum value.
-56
math
105
Given the function $f(x)=\sin(2ωx-\frac{π}{6})$, the graph is shifted to the left by $\frac{π}{4}$ units to obtain the graph of function $g(x)$. The graph of function $g(x)$ is symmetric about the $y$-axis. If $ω$ is the smallest positive number for which the transformation is valid, then $ω=$ \_\_\_\_\_\_.
ω=\frac{4}{3}
math
93
Let $f(x)=x^{2}+6 x+7$. Determine the smallest possible value of $f(f(f(f(x))))$ over all real numbers $x$.
23
math
36
Find the point \( M' \) symmetrical to the point \( M \) with respect to the line. \( M(3, 3, 3) \) \[ \frac{x-1}{-1} = \frac{y-1.5}{0} = \frac{z-3}{1} \]
(1, 0, 1)
math
70
\(\frac{\sin 6 \alpha}{\sin 2 \alpha} + \frac{\cos (6 \alpha - \pi)}{\cos 2 \alpha}\).
2
math
38
There are \_\_\_\_\_\_ six-digit numbers composed of three distinct odd numbers, two 2's, and one 0. (Answer with a number)
3000
math
35
Given the equation of the parabola $y=-2x^{2}+1$, determine the equation of the parabola after it is shifted $3$ units to the right and then $1$ unit down.
-2(x-3)^{2}
math
46
$\triangle ABC$ has a right angle at $C$ and $\angle A = 30^\circ$. If $BD$ ($D$ in $\overline{AC}$) is the bisector of $\angle ABC$, then find the measure of $\angle BDC$.
60^\circ
math
57
Find the number of positive integers $n \le 1500$ that can be expressed in the form \[\lfloor x \rfloor + \lfloor 2x \rfloor + \lfloor 4x \rfloor = n\] for some real number $x.$
856
math
63
If the graph of the function $f(x) = |x+m| + |nx+1|$ is symmetric about $x=2$, then the set $\{x | x = m+n\} = \quad$.
\{-4\}
math
46