content string | quality_label int64 | meta string | all-MiniLM-L6-v2_embedding list | doc_id int64 | unique_id string |
|---|---|---|---|---|---|
Not quite getting this trig stuff
September 3rd 2007, 04:52 PM #1
Junior Member
Joined
Nov 2006
Posts
42
Not quite getting this trig stuff
hi guys.
currently studying some maths at university, and they assume a whole bunch of high school maths knowledge. problem is, i was at high school 7 years ago,... | 4 | [
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Simplifying a polynomial
up vote 4 down vote favorite
1
Let $f(x_1,\ldots, x_n)\in\Bbbk [x_1,\ldots,x_n]$ be a given polynomial (assume $\Bbbk$ algebraically closed if you want). Suppose that we are given $n$ polynomials $v_1,\ldots v_n \in\Bbbk[x_1,\
ldots, x_n]$. Suppose that we know that there exists a polynomial $... | 4 | [
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0.07... | 38,601 | 38601 | |
Another card puzzle
I seem to have accumulated a backlog of subject matter that I have found interesting recently. I’ll get back to it soon… but right now, in the spirit of not getting back to work just yet, following
is another puzzle involving a card game. I found this problem in Peter Winkler’s Mathematical Puzzl... | 5 | [
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0.04150... | 38,602 | 38602 | |
Linear Equations
November 16th 2008, 01:38 PM
ChrisBarrett
Linear Equations
Hello, I have been having trouble with these 3 questions that are on my upcoming test. I have tried it many times without getting an answer and I could really use some help.
Here are the questions:
1)
2x - 3y = 5
4y + 2z ... | 4 | [
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Square + Quad
August 15th 2009, 09:37 PM #1
MHF Contributor
Joined
Dec 2007
From
Ottawa, Canada
Posts
3,080
Thanks
66
Square + Quad
Square UVWX; A on UX, B on UV, C on VW, D on WX.
Area square UVWX = twice area quadrilateral ABCD.
Perimeter ABCD = 800. All side lengths are integers.
... | 4 | [
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0.0... | 38,604 | 38604 | |
Speech Compression
Contents
I. Introduction
The compression of speech signals has many practical applications. One example is in digital cellular technology where many users share the same frequency bandwidth. Compression allows... | 4 | [
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... | 38,605 | 38605 | |
General integer solution for $x^2+y^2-z^2=\pm 1$
up vote 5 down vote favorite
4
How to find general solution (in terms of parameters) for diophantine equations $x^2+y^2-z^2=1$ and $x^2+y^2-z^2=-1$?
It's easy to find such solutions for $x^2+y^2-z^2=0$ or $x^2+y^2-z^2-w^2=0$ or $x^2+y^2+z^2-w^2=0$, but for these ones I... | 5 | [
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I'm having some algebraic difficulties: Help Please! Also Integration
July 12th 2007, 03:36 PM
googoogaga
I'm having some algebraic difficulties: Help Please! Also Integration
1) Could you please demonstrate the algebra going from
1/4 ln (u) = sinx + c to [u]=Ae^(4sin(x)) and How is the second function simi... | 5 | [
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0.036... | 38,607 | 38607 | |
Quadratic Farkas' Lemma?
up vote 11 down vote favorite
3
The Farkas Lemma says that if a system of linear inequalities implies yet another linear inequality, then this last inequality can be obtained by taking a positive linear combination of the
inequalities from the system. The precise statement is as follows:
... | 5 | [
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cartesian coordinates
October 25th 2009, 07:53 AM #1
Junior Member
Joined
Jun 2009
Posts
35
cartesian coordinates
1. Points A, B and C are the three vertices of a triangle in 3D space (Cartesian coordinate system). It is known that
AB = (3,6,1) BC = (0,-7,-4) CA = (-3,1,3)
(a) Is triangle ABC a r... | 4 | [
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Alternate Forms of the Derivative Formula
Date: 10/06/2001 at 23:37:55
From: Dina
Subject: Equivalent Forms of the Derivative Formula
I am a first-year AP Calculus student and I understand the notion of
the derivative and how/why the derivative of f at x is the limit as
h approaches 0 of [f(x + h)- f(x)]/h, but I am... | 4 | [
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Flipping coins on a budget
up vote 49 down vote favorite
18
A coin is flipped $n$ times and you win if it comes up heads at least $k$ times. The coin is unusual in that you're allowed to pick the probability $p_i$ that it comes up heads on the $i$th flip,
subject only to the constraint that $\sum_i p_i \le b$, where $... | 5 | [
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Correlation coefficient
October 9th 2009, 09:59 PM #1
Newbie
Joined
Oct 2009
Posts
13
Correlation coefficient
i have another qns here
if the correlation coefficient between X and Y is ρxy=1
how to prove that σ(X+Y) = σX + σY ?
Hello,
By definition, $1=\rho_{XY}=\frac{cov(X,Y)}{\sigma_... | 4 | [
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Is the set of cube-free binary sequences perfect?
up vote 13 down vote favorite
2
This question is inspired by this one. In that thread, it's established that there are uncountably many cube-free infinite binary strings (where $x \in 2^{\omega}$ is cube-free iff $\forall \sigma \
subset x,\ \sigma \sigma \sigma \not \... | 5 | [
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initial value problem
September 1st 2009, 05:16 PM #1
Junior Member
Joined
Aug 2007
Posts
71
initial value problem
y' + 7/2y = 1 - 1/7t y(0) = y0
Find the value for yo for which the solution touches, but does not cross, the t-axis. I understand that you solve for y0 and substitute it back into the e... | 5 | [
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0.05... | 38,614 | 38614 | |
Complement of a subgroup
October 28th 2012, 02:05 PM #1
Newbie
Joined
Aug 2012
From
india
Posts
5
Complement of a subgroup
Let $G$ be a finite group. Suppose that every element of order $2$ of $G$ has a complement in $G$, then $G$ has no element of order $4$.
Proof. Let $x$ be an element of $G$ ... | 5 | [
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Z-Transforms With MATLAB
Assume we have a transfer function in the z-domain given by
z 1
X z
z
1 2
2 .
1 0.25 z 0.375... | 5 | [
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Math Forum Discussions - Re: Finite Rings
Date: Feb 6, 2013 8:33 AM
Author: quasi
Subject: Re: Finite Rings
William Elliot <marsh@panix.com> wrote:
>
>[In forum "Ask an Algebraist", user "Anu" asks] (edited):
>
>> If R is a finite commutative ring without multiplicative
>> identity such that every nonzero element is a... | 4 | [
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Area of triangle in coordinate geometry
November 12th 2013, 04:44 AM
AaPa
Area of triangle in coordinate geometry
Hello friends.
There is a formula for area of a triangle in coordinate geometry which is as follows.
$\frac{1}{2}|x_1(y_2 - y_3)+x_2 (y_3 - y_1)+x_3 (y_1 - y_2)|$
I do not understand so... | 4 | [
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The relative homotopy sets $\pi_1(U_n,U_n/O_n)$ and $\pi_1(U_{2n},U_{2n}/USp_{2n})$
up vote 2 down vote favorite
1
During my research I have recently stumbled upon the problem of finding the relative homotopy sets $\pi_1(U_n,U_n/O_n)$ and $\pi_1(U_{2n},U_{2n}/USp_{2n})$ for $n$ large enough to be in the stable
regime ... | 5 | [
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Module 5.1: Simple, Joint, Marginal and Conditional Probabilities
Module 5.1 Notes
"Simple, Joint, Marginal and Conditional Probabilities"
Our last modu... | 4 | [
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Math Forum Discussions
Luis A. Afonso
Posts: 4,613
From: LIsbon (Portugal)
Registered: 2/16/05
Chi-squared to normal approximation
Posted: May 18, 2013 6:47 PM
Our remote colleagues Wilson, E. B. & Hilferty M. M., did provide a paper: The distribution of chi-square able to attain the transformation Chi-squared to Sta... | 4 | [
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Is this surface diffeomorphic to a sphere(S^2)?
up vote 1 down vote favorite
let $f:R^3 -> R \ \ \ \ \ \ \ \ f(x,y,z)=x^4 + y^6 +z^8 \\$
$M = f^{-1}(1)$
Is M is diffeomorphic to a sphere $S^2$ ?
I tried to solve this problem, but I realized that I have no tools to solve it.
Constant rank theorem tells me M is a sm... | 5 | [
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The Gysin long exact sequence for the complement of the zero section of a line bundle over a (possibly) singular base
up vote 3 down vote favorite
2
Let $pr:X\to Z$ be a line bundle of (possibly) singular varieties (that could be reducible) over a characteristic $p$ field ($p$ could be zero); $U$ is the complement to ... | 4 | [
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Line bundles and rational singularities
up vote 1 down vote favorite
Hi, I have some problem to understand the proof of lemma 3.2 of this article: http://www.ams.org/journals/jams/2001-14-03/S0894-0347-01-00368-X/.
The lemma states the following: Let $X$ be a variety and $f: Y \rightarrow X$ a resolution of singulari... | 5 | [
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Topic: proof of an inequality
Replies: 12 Last Post: Apr ... | 4 | [
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-0.05786132... | 38,625 | 38625 | |
Forming Functions from Verbal Descriptions
October 28th 2008, 07:39 PM #1
Newbie
Joined
Oct 2008
Posts
8
Hey, noob here. I was wondering if any of you smarter guys out there could help me out.
Coming from the textbook "Advanced Mathematics" by Richard Brown...
PROBLEM: Express the area A of a 30*... | 4 | [
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Kernel of Linear Transformation
December 4th 2012, 04:00 PM
aprilrocks92
Kernel of Linear Transformation
How does one find the kernel of a linear transformation? I have used row reduction to find the determinant of the following matrix, but do not know what it means to find the "kernel" of a linear
transform... | 5 | [
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0.0020904541015625,
-0.078125,
-0.06591796875,
0.051025390625,
-0.06298828125,
0.03979492... | 38,627 | 38627 | |
HELP!!! division & power properties of exponents
May 13th 2009, 01:10 PM #1
Newbie
Joined
Nov 2008
Posts
8
how would you solve this problem?
(3x^2 y)^-3
(3^3 x^-4 y^4)^-5
sorry, I don't know how to do superscript, so the ^ are to represent the exponents.
Hi mackenzie25,
$\frac{... | 4 | [
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0.00830078125,
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0.04931640625,
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0.0400390625,
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0.01977539... | 38,628 | 38628 | |
Probability and expected number of turns in coin flipping game?
January 3rd 2012, 03:00 AM #1
Probability and expected number of turns in coin flipping game?
Suppose we play a coin game: we flip a coin, upon tails you get one dollar from me, upon heads I get one dollar from you. We repeat this until one of us is ... | 5 | [
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0.04345703125,
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-... | 38,629 | 38629 | |
calculus-rate problem
Number of results: 40,004
calculus
My problem is that a stft above the sidewalk. a man 6ft tall walks away from the light at the rate of 3ft/sec. at what rate is his tip of shadow moving
July 26, 2011 by Abdul Muqsit
calculus
You are letting the air out of a hot air balloon at a steady rate. The... | 4 | [
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0.0177001953125,
-0.048828125,
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0.034912109375,
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-0.01263427734... | 38,630 | 38630 | |
Vanishing Trace
up vote 6 down vote favorite
2
Let $\mathcal H$ be a Hilbert space, and let $a \in \mathcal B(\mathcal H)$ satisfy $\mathrm{Tr}(a)=0$. If $a$ is self-adjoint, then we can find a vector $\xi \in \mathcal H$ such that $\langle \xi |
a \xi \rangle=0$. Is this true in general? Is it always possible to find... | 5 | [
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0.... | 38,631 | 38631 | |
matrix equation
Last edited by Tom123; November 7th 2007 at 06:37 AM.
Oh sorry... A= 2 0 a 2 2 1 8 a+3 4
$a = 3$ $b = \left ( \begin{matrix} 18 \\ 16 \\ 62 \end{matrix} \right )$ Solve $\left ( \begin{matrix} 2 & 0 & 3 \\ 2 & 2 & 1 \\ 8 & 6 & 4 \end{matrix} \right ) \cdot \left ( \begin{matrix} x_1 \\
x_2 \\ x_3 \end... | 5 | [
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0.06982421875,
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-0.06640625,
0.0218505859375,
0.09716796875,
-0.0947265625,
0.0598... | 38,632 | 38632 | |
Bounding a signed sum of complex numbers
up vote 0 down vote favorite
1
Let $z_i \in \mathbb{C}\:$ for $i=1,\dots, n\;$ be complex numbers, all with absolute value $|z_i|\le 1\;$.
Prove (or disprove) that there exists a choice of signs $s_i \in \{\pm 1\}$ such that $$\left|\sum_{i=1}^n s_i\cdot z_i\right| \le \sqrt{2... | 5 | [
-0.039794921875,
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0.0181884765625,
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-0.06689453125,
0.08642578125,
-0.02... | 38,633 | 38633 | |
probability question
Member
Registered: 2006-07-06
Posts: 251
Re: probability question
Member
Registered: 2007-10-15
Posts: 11
probability question
Hi
I'm after some info on how to work out probability using poker hands.
I've been told that if i hold two different cards in my hand the chan... | 5 | [
-0.048095703125,
-0.007781982421875,
0.040283203125,
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0.047119140625,
-0.057861328125... | 38,634 | 38634 | |
Question about logs
June 5th 2009, 07:45 AM
s3a
Question about logs
I am studying for an end of year exam and I completely forgot everything about logs and log functions (except for the extreme basics) so can someone tell me why the answer is D by showing me all
the steps?
Any help would be greatly appr... | 4 | [
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-0.0927734375,
0.045166015625... | 38,635 | 38635 | |
Permutations & Combinations
October 20th 2008, 06:28 AM #1
Member
Joined
Jan 2008
Posts
132
Permutations & Combinations
Q: Find out how many 3 figure numbers, lying between 100 and 999 inclusive, have 2 and only 2 consecutive figures identical.
Thank you for helping! ^^
Reply
You can choose $\... | 4 | [
-0.027587890625,
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0.06591796875,
0.01611328125,
-0.005859375,
-0.0322265625,
0.0058898925781... | 38,636 | 38636 | |
Taylor + Power Series
May 1st 2008, 05:15 AM
bakanagaijin
Taylor + Power Series
I was having some trouble with these:
1. Find the Taylor polynomial of degree 4 centered at c=2 for the function $f(x)=\sqrt[3]{x}$
2. Given $e \approx 1 + 1 + {1^2\over2!}+ {1^3\over3!}+ {1^4\over4!}+ {1^4\over4!}$, use Ta... | 5 | [
0.025634765625,
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0.038818359375,
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-0.00640869140625,
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0.07861328125,
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-0.00360107421875,
-0.053955078125,
-0.07177734375,
-0.00787353515625,
-0.06347656... | 38,637 | 38637 | |
Proving type of quadrilateral by its diagonal lengths
June 11th 2011, 12:58 PM #1
Member
Joined
Mar 2011
Posts
99
Hi Forum
Is there an easy and objective way to find the type of quadrilateral just by its diagonal lengths? I mean, with no calculation.
If we were to find the area of a quadrilateral... | 5 | [
0.052734375,
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0.00885009765625,
0... | 38,638 | 38638 | |
Math sin/cos
Number of results: 94,429
TRIG!
Posted by hayden on Monday, February 23, 2009 at 4:05pm. sin^6 x + cos^6 x=1 - (3/4)sin^2 2x work on one side only! Responses Trig please help! - Reiny, Monday, February 23, 2009 at 4:27pm LS looks
like the sum of cubes sin^6 x + cos^6 x = (sin^2x)^3 + (cos^2x)^3 = (sin^2x+... | 4 | [
-0.09228515625,
0.031982421875,
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0.044921875,
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0.037353515625,
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0.0037078857421875,
-0.004119873046875,
0.0771484375,
-0.018798828125,
-0.046875,
0.0164794921875,
... | 38,639 | 38639 | |
Units of Local Rings
March 10th 2009, 06:39 PM
electricjaguar
Units of Local Rings
Hi, I'm trying to prove that the units of a local ring R with maximal ideal M are exactly the elements of R-M. I checked Google and there are proofs available, so I don't need a full proof, I
just have 2 questions about the pr... | 4 | [
-0.01165771484375,
0.07763671875,
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0.0133056640625,
0.024169921875,
-0.076171875,
0.126953125,
0.0126953125,
-0.0322265625,
-0.04150390625,
-0.03857421875,
-0.04150390625,
0.125,
-0.055908203125,
-0.0035247802734375,
0.049072265625,
0.06640625,
0.0322265625,
-0... | 38,640 | 38640 | |
Circle Formulas: Area and Perimeter
Date: 03/19/2003 at 16:52:32
From: Leo
Subject: Math formulas
I get confused with the different formulas, such as Pi r squared or
Pi d (Pi times radius squared or Pi times diameter). I don't remember
which formula goes to which problem.
Date: 03/21/2003 at 13:45:56
From: Doctor D... | 4 | [
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0.07177734375,
0.04052734375,
0.041748046875,
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-0.000720977783203125,
... | 38,641 | 38641 | |
Parabola, vertex-focus distance
August 16th 2012, 04:21 PM #1
Parabola, vertex-focus distance
A spotlight has a parabolic cross section that is 4 ft wide at the opening and 1.5 ft deep at the vertex, how far is the vertex from the focus?
I'm quite confused as my textbook gives no illustration, im assuming th... | 4 | [
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0.0186767578125,
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0.0203857421875,
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0.083984375,
-0.0128173828125,
-0.14453125,... | 38,642 | 38642 | |
A Cauchy problem for an iterated Euler-Poisson-Darboux eqaution
up vote 1 down vote favorite
Good morning,
I'm interested in solving a Cauchy problem for the iterated singular EPD.
Well, Weinstein (On a class of PDEs of even order, 1955) showed how the decomposition formula leads to the solution of the Cauchy proble... | 4 | [
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-0.103515625,
0.0262451171875,
0.00811767578125,
-0.05615234375,
-0.04833... | 38,643 | 38643 | |
appF
APPENDIX F. TRANSFORMS, COMPLEX ANALYSIS 1
Appendix F
Transforms, Complex
Analysis
This appendix discusses Fourier and Laplace transforms as they are used in
plasma physics and this book. Also, key properties of comp... | 4 | [
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0.00048828125,
0.007720947265625,
-0.1181640625,
-0.06884765625,
0.0085449218... | 38,644 | 38644 | |
Black Scholes Monte Carlo in Python
November 16, 2011 – 4:00 pm
The Black Scholes formula is a partial differential equation that can be used to price the present value of an option under certain assumptions. As with everything, you can read all about it in
Wikipedia.
It turns that that figuring out the present value... | 5 | [
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-0.046630859375,
0.021240234375,
0.00355... | 38,645 | 38645 | |
Finding minimal or canonical expressions for Boolean truth tables
up vote 7 down vote favorite
2
This is not an urgent question, but something I've been curious about for quite some time.
Consider a Boolean function in n inputs: the truth table for this function has 2^n rows.
There are uses of such functions in, for... | 5 | [
0.0201416015625,
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0.04150390625,
0.040771484375,
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0.0050048828125,
-0.0211181640625,
0.0693359375,
-0.016357421875,
0.0578... | 38,646 | 38646 | |
A Napierian logarithm before Napier
In the ordinary histories of mathematics there are very few suggestions about the way in which John Napier conceived the idea of his great discovery, truly one of the most beautiful made by man, not
only As supplying a new method for saving time and trouble in tedious calculations, b... | 5 | [
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0.0174560546875,
-0.0478515625,
-0.0211181640625,
-0.08251953125,
0.0... | 38,647 | 38647 | |
Expressing power sum symmetric polynomials in terms of lower degree power sums
up vote 9 down vote favorite
5
Is there an explicit formula expressing the power sum symmetric polynomials $$p_k(x_1,\ldots,x_N)=\sum\nolimits_{i=1}^N x_i^k = x_1^k+\cdots+x_N^k$$ of degree $k$ in $N < k$ variables entirely
through the powe... | 5 | [
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-0.02197265625,
0.0732421875,
0.08203125,
0.0196533203125,
... | 38,648 | 38648 | |
(Graph Theory)Prove that graph X is a tree.
July 21st 2011, 09:28 AM #1
Newbie
Joined
Oct 2009
Posts
3
(Graph Theory)Prove that graph X is a tree.
Let X be a graph with ONLY one spanning tree. Prove that X is a tree.
What I proved so far is that X is connected since all graphs with a spanning tree s... | 4 | [
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-0.006988525390625,
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0.060302734375,
-0.03466796875,
0.021... | 38,649 | 38649 | |
Arithmetic Sequences
February 21st 2013, 07:42 AM #1
Member
Joined
Feb 2013
From
Canada
Posts
131
Farmers near Raymond, Alberta, use a wheel line irrigation system to provide water to their crops. A pipe and sprinkler system is attached to a motor-driven wheel that moves the system in a
circle ove... | 4 | [
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0.03662109375,
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0.0240478515... | 38,650 | 38650 | |
[SOLVED] Need help...is there an equation to solve this easily?
December 10th 2009, 09:28 AM
elleg
[SOLVED] Need help...is there an equation to solve this easily?
I'm new to this site, and I apologize if I've put this question in the wrong forum, but I really wasn't sure where it should go. This is not for a cla... | 5 | [
-0.01287841796875,
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0.01312255859375,
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0.01385498046875,
0.0162353515625,
0.01953125,
-0.109375,
-0.040... | 38,651 | 38651 | |
Differentiation Questions
April 26th 2010, 03:30 AM
Paymemoney
Differentiation Questions
Hi
Can someone tell me if my answers are correct for the following questions:
1) Find the slope of the graph $y=2x^3 + 4\sqrt{x}$ at x = 2
$\frac{dy}{dx} = 6x^2 + 2x^{\frac{-1}{2}}$
when x = 2
$\frac{... | 5 | [
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0.01953125,
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0.033935546875,
0.01007080078125,
0.06884765625,
0.095703125,
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0.03271484375,
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-0.06640625,
0.08056640625,
-0.091796875,
-0.03369140625,
-0.05053710... | 38,652 | 38652 | |
distribution of non-solvable group orders
up vote 4 down vote favorite
1
let $M$ be the set of natural numbers such that there is a group of this order, which is not solvable. what is the minimal distance $D$ of two numbers in $M$?
the examples $660$ and $672$ show $D \leq 12$. the famous theorem of feit-thompson imp... | 5 | [
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-0.0234375,
-0.01495... | 38,653 | 38653 | |
Characteristic Function of a Non-negative Random Variable Evaluated at a Complex Value
up vote 1 down vote favorite
Suppose we have a non-negative random variable $X$ with density $p(x)$,and its characteristic function, evaluated at a complex number $z$, being $\phi(z)=E[e^{z X}]=\int_{0}^{\infty}e^{zx}p(x)dx$.
It se... | 5 | [
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0.0162353515625,
-0.03466796875,
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0.0008544921875,
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0.01434326171875,
0.033935546875,
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0.10009765625,
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-... | 38,654 | 38654 | |
I NEED MAJOR HELP!(Question on Polynomials)
September 25th 2007, 06:54 PM
zarlock99
I NEED MAJOR HELP!(Question on Polynomials)
Ok so this is my tips question which is due tomorrow for marks and I havnt been able to think how to do it.
The Volume of a cylindrical can is
4(pi)x^3 + 28(pi)x^2 + 65(pi)x + ... | 4 | [
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0.0673828125,
-0.038330078125,
-0.032470703125,
0.0128173828125,
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0.06640625,
0.087890625,
0.0240478515625,
-0.0257568359375,
-0.046630859375,
0.0712890625... | 38,655 | 38655 | |
Small and large pieces of the plane, after countably many generic straight cuttings
up vote 6 down vote favorite
1
A delightful recent problem about disconnecting the plane by straight lines suggested me the following further question, that I can't resist to post.
Let $\mathcal{F} $ be a countable family of straight ... | 4 | [
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0.083984375,
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-0.048583984375,
-0.0976... | 38,656 | 38656 | |
Probability of a Boy
Member
Registered: 2013-03-19
Posts: 1
Re: Probability of a Boy
Member
Registered: 2013-03-03
Posts: 6
Re: Probability of a Boy
MathsIsFun wrote:
"I tell you I have two children and that (at least) one of them is a boy, ... your right answer to my question is not 1/... | 4 | [
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0.01708984375,
0.04345703125,
-0.00653076171875,
-0.0177001953125,
-0... | 38,657 | 38657 | |
A binomial identity
November 12th 2008, 12:17 PM #1
A binomial identity
I'm trying to give a combinatorial proof of the following identity:
$\sum_{k=0}^{n} 2^k \binom{n}{k} \binom{n-k}{\lfloor \frac{n-k}{2} \rfloor}=\binom{2n+1}{n}$
***
On the right side, $\binom{2n+1}{n}$ is the number of $n$-ele... | 4 | [
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0.0888671875,
0.03857421875,
-0.069335... | 38,658 | 38658 | |
Limit probability
up vote 3 down vote favorite
1
You start with a bag of N recognizable balls. You pick them one by one and replace them until they have all been picked up at least once. So when you stop the ball you pick has not been picked before
but all the others have been picked once or more.
Let $P_N$ be the pr... | 5 | [
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... | 38,659 | 38659 | |
Question on Optimization
December 8th 2009, 12:03 AM #1
Newbie
Joined
Jun 2009
Posts
6
Question on Optimization
I have posted this problem in the applied math section. Curious to hear what people here would say.
I have a (maybe trivial?) question on constrained optimization. Assume that I have the f... | 4 | [
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0.0517578125,
-0.085... | 38,660 | 38660 | |
Substituting definate integrals
August 10th 2007, 06:54 PM #1
Member
Joined
Jun 2007
Posts
79
Substituting definate integrals
I have been having problems substituting and one instance of basic integration. 1 and 3 are subs and 2 is the basic integration (I believe)
1. /int (sqrt pi)_0 x(cos x)^2 the ... | 5 | [
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0.00119781494140625,
0.0... | 38,661 | 38661 | |
Counter-intuitive? or...
April 2nd 2007, 07:20 AM #1
Counter-intuitive? or...
A car travels from point X to point Y. It travels at 30 km/h up to halfway and at 20 km/h for the rest of the journey. What is the car's average speed?
The answer seemed pretty simple at first, I mean, it's got to be 25 km/h. Since... | 4 | [
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0.0234375,
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0.01318359375,
0.037109375,
0.0205078... | 38,662 | 38662 | |
Linear transformations
January 11th 2009, 07:06 AM #1
Junior Member
Joined
Dec 2008
Posts
30
Linear transformations
I'm stuck with the problem:
1. does a linear transformations (T:R3 to R3) exists that follwing these terms:
T(1,0,1)=T(2,1,2)=T(0,1,1)=T(2,3,3)
if there is give an example for s... | 5 | [
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0.020751953125,
-0.03271484375,
-0.032958984375,
-0.0693359375,
-0.0278320312... | 38,663 | 38663 | |
gamma function
gamma function, generalization of the factorial function to nonintegral values, introduced by the Swiss mathematician Leonhard Euler in the 18th century.
For a positive whole number n, the factorial (written as n!) is defined by n! = 1 × 2 × 3 × … × (n − 1) × n. For example, 5! = 1 × 2 × 3 × 4 × 5 = 120... | 4 | [
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0.0054931640... | 38,664 | 38664 | |
The counting principle: permuations and combinations
Permutation and Combinations Handout
Section 1: the counting principle
7. How many sequences of two l... | 4 | [
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-0.0654296875,
-0.05371... | 38,665 | 38665 | |
Inverse trig functions
April 15th 2008, 06:30 PM
>_<SHY_GUY>_<
Inverse trig functions
one thing to just clear out...im kinda blank today...why is cosine of 0 = 1 and sine of 0 = 0?
how is arctan square root of 3 divided by 3 = pi/6?
how is (arctan x = pi/4) equal to 1?
how is (arctan x = -pi/6) eq... | 5 | [
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0.00... | 38,666 | 38666 | |
Axioms for Riemann $\zeta$ function
MathOverflow is a question and answer site for professional mathematicians. It's 100% free, no registration required.
Are there any set of axioms that completely characterize the Riemann zeta function? i.e. like Ressayre axioms for the exponential function... | 4 | [
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Number of forests of size $i$ and the Tutte polynomial
up vote 2 down vote favorite
In "The Potts model and the Tutte Polynomial", D.J.A. Welsh and C. Merino claim on pg. 1135, equation 18, that, \begin{align*} \sum_{i=0}^{n-1}f_i t^i = t^{n-1}T_G(1+\frac{1}{t},1) \end{align*} where
$T_G(x,y)$ is the Tutte polynomial ... | 5 | [
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-0... | 38,668 | 38668 | |
question: matrix division
November 18th 2012, 02:54 AM #1
Newbie
Joined
Nov 2012
From
philippines
Posts
3
question: matrix division
i just want to know if its possible to divide matrix?
ive run through many mathbooks and i found no matrix division just addition and multiplcation.. can someone en... | 5 | [
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0.03271484375,
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0.0252685546875,
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0.053466796875,
0.060546875,
-0.0023193359375,
0.027099609375,
-0.04248046875,
0.0058593... | 38,669 | 38669 | |
Axiom of Infinity needed in Cantor-Bernstein?
Take the 2-minute tour ×
MathOverflow is a question and answer site for professional mathematicians. It's 100% free, no registration required.
Can one prove the Cantor-Bernstein (or Schröder-Bernstein) theorem without using the Axiom of Infinity?
set-theory
By the ... | 4 | [
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0.01226806640625,
-0.02197265625... | 38,670 | 38670 | |
Pythagorean Theorem for Right-Corner Hyperbolic Simplices?
up vote 10 down vote favorite
4
My answer to the "Favorite Equations" question was the Pythagorean Theorem for Right-Corner Tetrahedra:
Euclidean: $A^2+B^2+C^2=D^2$
Hyperbolic: $\cos\frac{A}{2}\cos\frac{B}{2}\cos\frac{C}{2}−\sin\frac{A}{2}\sin\frac{B... | 4 | [
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-0.001495361328125,
-0.0036... | 38,671 | 38671 | |
Find Max Value Based on F' Graph
April 20th 2009, 03:02 PM #1
Newbie
Joined
Jan 2009
Posts
24
Find Max Value Based on F' Graph
The graph of f', the derivative of the function f, is shown above for x on the closed interval of [0,10]. The areas of the regions between the graph of f' and the x-axis are... | 5 | [
0.02978515625,
0.0224609375,
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0.08251953125,
0.07470703125,
0.06689453125,
-0.031982421875,
-0.058349609... | 38,672 | 38672 | |
How to study the behavior of a particular function on a Vector Space.
up vote 1 down vote favorite
1
Let, $V$ be a vector space over a field $K.$ Let, $T$ be a function from $V$ to $V$ such that $T(kX) = kT(X)$ for all $k \in K$ and for all $X \in V$ and also $T(k + X) = T(X)$ for all $k \in K$ and
for all $X \in V$.
... | 4 | [
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0.01953125,
-0.00982666015625,
0.056884765625,... | 38,673 | 38673 | |
simplify recurrence relation
June 7th 2010, 09:25 PM #1
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Joined
Jun 2010
Posts
3
simplify recurrence relation
I'm trying to solve this for b:
b*2^n = 3*b*2^(n-1) + 2^n
the answer is:
b = -2^(n + 1)
but i don't see how to get there.
can someone enlighten me?
thanks
... | 5 | [
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0.0615234375,
-0.016357421875,
-0.088867... | 38,674 | 38674 | |
How should an analytic number theorist look at Bessel functions?
up vote 27 down vote favorite
15
(And a related question: Where should an analytic number theorist learn about Bessel functions?)
Bessel functions occur quite frequently in analytic number theory. One example, Corollary 4.7 of Iwaniec and Kowalski, says... | 4 | [
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0.0263671875,
0.0534... | 38,675 | 38675 | |
Can anyone solve this?
April 27th 2005, 01:44 AM #1
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Apr 2005
Posts
21
The set {1,2,3,4} can be partitioned into two subsets {1,4} and {2,3} of the same size. Notice that 1+4 = 2+3
a)Find the next whole number n, above 4, for which the set {1,2,...,n} can be partitioned into two sub... | 4 | [
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-0.0198974609375,
0.06005859375,
-0.0185546875,... | 38,676 | 38676 | |
Best strategy for small resolutions
up vote 12 down vote favorite
7
I would like to know if there is a standard technique to check if a singular variety admits a small resolution. What are the main references for these types of questions?
I am mostly interested in threefolds and fourfolds with singularities in codime... | 4 | [
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0.0172119140625,
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0.04394... | 38,677 | 38677 | |
Standard form - Mathematics
Standard form
Standard form is way of expressing numbers that are either very large or too small to use. Take for example the number;
1,000,000,000,000,000,000,000,000
This is such a very huge number to read or write. It would be incredibly hard to use in any maths calculation and you wou... | 4 | [
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0.1142578125,
0.03125,
0.072265625,
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0.0400390625,
0.055419921875,
0.01318359375,
-0.053955078125,
-0.06640625,
0.008483886718... | 38,678 | 38678 | |
Hyperbolic Triangle
April 24th 2011, 11:47 PM #1
Banned
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Apr 2011
Posts
21
Hyperbolic Triangle
We are presented with the problem:
The hyperbolic lines l, m and n defined by:
l={zEH | abs(z-1)=2}
m={zEH | Re(z)=2}
n={zEH | abs(z-3)=2rt3}
form a hyperbolic triangle with vertice... | 5 | [
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0.042236328125,
0.00823974609375,
-0.055908203125,
-0.1030... | 38,679 | 38679 | |
the hopf invariant of the hopf construction
up vote 6 down vote favorite
3
I'm having some trouble with a problem about the Hopf construction, in the exercises for Ch. 4 of Mosher & Tangora. Given a map $g : S^{n-1} \times S^{n-1} \rightarrow S^{n-1}$, we get a map $h(g) :
S^{2n-1} \rightarrow S^n$ by considering
$S^... | 4 | [
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0.03125,
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-0.0986328125,
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0.10009765625,
0.000047206878662109375,
0.0... | 38,680 | 38680 | |
Finding the equation of a tanget line(derivative error)
October 10th 2010, 10:59 AM #1
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Joined
Jul 2010
Posts
17
Finding the equation of a tanget line(derivative error)
In order to find the equation of a tanget line, you need the slope.
the problem I was given is
f(x) = $((x^3)+4x-1)(x-2)... | 4 | [
-0.043701171875,
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0.087890625,
-0.0263671875,
-0.024658203125,
0.0849609375,
-0.0810546875,
-... | 38,681 | 38681 | |
test for the series for convergence or divergence 3
determine if series is convergent or divergent the sum from 1 to infinity of (-1)^n(2^(1/n))
Its somewhat similar to your other problem here. Whenever you have a $\left(-1\right)^n$ term, you should always first start off with the alternating series test. The absolut... | 5 | [
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-0.08642578125,
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0.035400390625,
-0.10595703125,
... | 38,682 | 38682 | |
epidemic model help
March 2nd 2008, 11:27 PM #1
Newbie
Joined
Mar 2008
Posts
11
epidemic model help
Hi I'am new here just looking for some help with this model, I dont know how to begin.
ok
So I have -
(x should be lamder and a alpha..)
dn/dt = kn(1-xn^a)
for no. of flies n(t) whe... | 5 | [
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Derivatives and Graphs
October 5th 2008, 04:00 PM
Pandora
Derivatives and Graphs
Hi.
I would appreciate some help with a couple of calculus questions I'm battling with. For the first one:
Why is that a positive value at a turning point indicates a minimum for thr second derivative test? An example would... | 5 | [
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Probability for Rolling Two Dice |Sample Space for Two Dice |Worked-out Problems
Probability for Rolling Two Dice
Probability for rolling two dice with the six sided dots such as 1, 2, 3, 4, 5 and 6 dots in each die.
When two dice are thrown simultaneously, thus number of event can be 6
^2
= 36 because each die has... | 4 | [
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0... | 38,685 | 38685 | |
Algebraic Rearrangement
August 9th 2011, 08:15 AM #1
Newbie
Joined
Aug 2011
Posts
4
Algebraic Rearrangement
Hi, I'm new to this site and I hope you guys can help. I'm not actually pre university but an engineer, yet I'm having some problems rearranging an equation and was hoping someone could help. The
... | 4 | [
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Minimal distance spheres in complex projective spaces
up vote 5 down vote favorite
My question has to do with distance spheres in $\mathbb CP^{n+1}$. I am interested in knowing what is the radius $r$ of a distance sphere $S(r)$ around a point that makes it a minimal submanifold
of $\mathbb CP^{n+1}$. It is kno... | 5 | [
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Wood Flooring
Date: 08/09/97 at 18:18:45
From: Paul Taylor
Subject: Production
Estimating the number of linear feet in 1 sq. ft.
Making wood flooring, width is 3.25 inches.
Goal is to produce 5,000 sq. ft. per day.
Date: 08/10/97 at 03:07:57
From: Doctor Mike
Subject: Re: Production
Hi Paul,
Let me make sure I u... | 4 | [
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What holomorphic functions are limits of polynomials?
up vote 11 down vote favorite
2
Let $\Omega$ be a connected open set in the complex plane. What is the closure of the polynomials in $\mathcal{H}(\Omega)$ the set of holomorphic functions on $\Omega$? The topology is the usual
compact convergence topology. Take, fo... | 5 | [
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Inventing Relativity, 1860s styleInventing Relativity, 1860s style
By the 1860s, the classical theory of electricity and magnetism was on a very solid theoretical footing. Maxwell’s equations describing the interplay of charges and currents with electric and
magnetic fields were on paper by 1862, and with some changes ... | 4 | [
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Dirac measures dense in space of measures?
up vote 1 down vote favorite
1
Let $I$ be a compact interval and $\mathcal{M}(I)$ the space of (signed) Borel measures. We equip it with the weak topology, i.e. a sequence $\mu_n$ converges to zero if and only if $$ \left|\int_I f
(x) \mathrm{d}\mu_n(x)\right| \longrightarrow... | 5 | [
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0.0810546875... | 38,691 | 38691 | |
JMAP_LESSON_PLANS_Graphing_and_Writing_Linear_Equations
Objective: Graphing and Writing Linear Equations: Solving Problems withPage 1 of 5
Math A Lesson Plans by Topic (www.jmap,org)
Resources:
TI 83+ graphing calculator... | 4 | [
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size of a charge
January 26th 2011, 09:29 AM #1
Member
Joined
Nov 2009
Posts
94
size of a charge
1. The problem statement, all variables and given/known data
Hi
I need clarification on this problem. Calculate
a) the force between 2 charges of +1.4nC and +1.6nC on point conductors 40cm apart i... | 4 | [
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Please help me with this(ratio of the volume)
April 2nd 2008, 01:04 AM #1
Newbie
Joined
Oct 2007
Posts
12
Please help me with this(ratio of the volume)
A prism with height 2cm and a pyramid with height 5cm have congruent triangular base. Find the ratio of their volumes.
.
.
.
.
.
... | 4 | [
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Number theory question i'm stuck on during exam revision
January 14th 2010, 06:58 AM #1
Newbie
Joined
Jan 2010
Posts
15
Number theory question i'm stuck on during exam revision
Let a, b, q, r be integers such that b=aq+r and a doesn't = 0. SHow that an integer c is a common divisor of b and a if and only... | 4 | [
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Writing equations in different forms
July 9th 2010, 11:18 AM #1
Newbie
Joined
Jul 2010
Posts
3
Writing equations in different forms
I have a few questions I need help with:
1. Can 2 different quadratic formulas have the same roots? Explain why or why not.
2. Write the vertex form of (x-6)(x+2)
... | 4 | [
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GAGA and Chern classes
up vote 15 down vote favorite
7
My question is as follows.
Do the Chern classes as defined by Grothendieck for smooth projective varieties coincide with the Chern classes as defined with the aid of invariant polynomials and connections on complex vector
bundles (when the ground field is $\mathb... | 4 | [
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modification of Doob inequality
up vote 1 down vote favorite
Hi everyone, please consider the following problem:
Let $(M_t)_{t\geq 0}$ be a continuous and positive submartingale and $S_t=\sup_{0\leq s\leq t}M_s$. Please prove that for any $\lambda>0$ we have
$$\lambda P(S_t>2\lambda)\leq E[M_t1_{\{M_t>\lambda\}}]$$
... | 5 | [
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Work down on the Upper bound of the Twin Primes
up vote 3 down vote favorite
This question already has an answer here:
It can be shown using the Selberg Sieve method, that the maximum number of Twin primes less than $N$ is $$\frac{CN}{\ln^2(N)}$$ does anyone know if there has been any work done on finding an upper
bo... | 4 | [
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-0.... | 38,699 | 38699 |