CELEBRITY NET WORTH — Apr 09
Motivation behind study of martingales
Today I wanted to ask a question which I am sure has been answered in multiple places but for which ...
![Prove this formula $1+\cos\theta+\cos2\theta+...+\cos n\theta=\frac{1}{2}+\frac{\sin(n+\frac{1}{2})\theta}{2\sin\frac{\theta}{2}}$ [duplicate]](https://f.mahou.org/image/prove-this-formula-1costhetacos2thetacos-nthetafrac12fracsinnfrac12theta2sinfractheta2-duplicate_474x274.jpg)
BUSINESS NEWS — Apr 09
Prove this formula $1+\cos\theta+\cos2\theta+...+\cos n\theta=\frac{1}{2}+\frac{\sin(n+\frac{1}{2})\theta}{2\sin\frac{\theta}{2}}$ [duplicate]
This is homework but I’m really stuck. The question is to prove a fromula which states: $$1+\cos\t...
CELEBRITIES ON SOCIAL MEDIA — Apr 09
Find a normal vector onto the line
How can I find normal vector on the given line. For example if I have a line $3x - 5y = 1$, what wou...
REGIONAL UPDATES — Apr 09
How many ways $12$ persons may be divided into three groups of $4$ persons each?
How many ways $12$ persons may be divided into three groups of $4$ persons each? I think the answer...
CULTURE — Apr 09
What is the meaning of the symbol "$\left|\underline{\;n\;}\right.$" for integer $n$?
For example, (6) The sequence of primes is endless. For, if $p$ is any prime, the number ${\...
CELEBRITY FLASHBACKS — Apr 09
How to represent a logic equivalence?
In propositional logic we have the DeMorgan's laws: $$\lnot (p\lor q) \Leftrightarrow \lnot ...
WEATHER NEWS — Apr 09
Calculate remainder of $12^{34^{56^{78}}}$ when divided by $90$
Calculate remainder of $12^{34^{56^{78}}}$ when divided by $90$ First of all,I'm not sure abou...
REGIONAL UPDATES — Apr 09
Difference in logic notations for maths and computer science
I am reading: How to prove it, A structured approach by Daniel J.Velleman and despite it being a boo...
ENERGY NEWS — Apr 09
Probability of Posting a Quad and Trip on 4chan
Important Pre-Requisite Knowledge On the image board 4chan, every time you post your post gets a 9 ...
TIKTOK TRENDS — Apr 09
Derivation of the energy equation in fluid dynamics
I'm working through Acheson's 'Elementary Fluid Dynamics' and i'm having tr...
CELEBRITY BIRTHDAYS — Apr 09
Calculate distance in 3D space
Imagine I want to determine the distance between points 0,0,0 and 1,2,3. How is this calculated?...
CELEBRITY FASHION LINES — Apr 09
What's 110 degrees counterclockwise from positive direction of x-axis?
What are the x and y components of a vector a with arrow in the xy plane if its direction is 110° c...
CLIMATE REPORTS — Apr 09
Goldschmidt division example with estimates?
I have found in Gonzalez/Diaz-Herrera/Tucker: Computing Handbook an example for the Goldschmidt divi...
WEATHER NEWS — Apr 09
How to derive the Riemann Curvature Tensor?
I'm taking a course in General Relativity, and before getting into Physics itself, the required...
CELEBRITY BODYGUARDS — Apr 09
Rate of Change of Volume in a Sphere
Assume that the radius $r$ of a sphere is expanding at a rate of $7$ in. /min. The volume of a spher...
CHILD STARS — Apr 09
How do you find the radius with only the slant height? Please show work.
The radius of the circle is 12cm, it is then made into a cone Question: A cone is made by joining ...
CHILD STARS — Apr 09
sum of all the numbers that can be formed using the digits 2,3,3,4,4,4..
How to find the sum of all the numbers that can be formed using the digits 2,3,3,4,4,4.. What should...
CELEBRITIES ON SOCIAL MEDIA — Apr 09
multiplication in H-space and loopspace of the H-space
Let $X$ be an $H-space$, and let a multiplication $,\cdot,$ be given, associative up to homotopy. L...
![Find the number of bicycles and tricycles [duplicate]](https://f.mahou.org/image/find-the-number-of-bicycles-and-tricycles-duplicate_474x274.jpg)
CELEBRITY MEMOIRS — Apr 09
Find the number of bicycles and tricycles [duplicate]
Help for my son. My math is a bit rusty and I'm trying to remember how to go about answering t...
CULTURE — Apr 09
Are there more even numbers than odd numbers?
Very simple 'yes-or-no' question, but I can't find the answer anywhere. My gut feelin...
FINANCIAL NEWS — Apr 09
Calculation of Radon–Nikodym derivative
Suppose the function $X \colon \mathbb{R} \longrightarrow \mathbb{R} \colon x \longmapsto X(x) : = x...
CLIMATE REPORTS — Apr 09
How do you get $\alpha$ from $\tan{\alpha}$?
How do you get $\alpha$ from $\tan{\alpha}$? Hello, I want to know how to obtain $\alpha$ from $\tan...
FINANCIAL NEWS — Apr 09
What is an anti chain
Which of the following is the correct definition of an anti chain .. 1). A subset S of a partially ...
![Sigma notation formula $i=0$ [closed]](https://f.mahou.org/image/sigma-notation-formula-i0-closed_474x274.jpg)
CELEBRITY FLASHBACKS — Apr 09
Sigma notation formula $i=0$ [closed]
I am trying to help a high school student to solve summation calculation problems. The $i$ value of ...
CELEBRITY BODYGUARDS — Apr 09
derivative with respect to constant.
I have been beating my head against this question for quite some time, I do not know whether it has ...
CLIMATE REPORTS — Apr 09
Function transformation: shrink horizontally
Write the formula for $f(x)$, if the graph of $f$ can be obtained from the graph of $y = g(x)$ by sh...
REGIONAL UPDATES — Apr 09
Eigenvectors in Matlab/Octave, function "eig()", why are the eigenvectors output like that? [closed]
You can calculate eigenvectors of a matrix with eig() function like this: [eigenvectors, eigenvalue...
FASHION NEWS — Apr 09
Inverse laplace transform of $\frac{1}{s^3(s-1)}$
I have a problem with this transform. I know that using this theorem (see the theroem) I can get the...
CHILD STARS — Apr 09
Drawing Plausible Phase Portrait
The equation: $$\dot{x} = f(x),\space x\in \mathbb{R},\space \text{where} \space f\begin{pmatrix}x_...
ENERGY NEWS — Apr 09
Can covariance be negative?
So I always thought that covariance could take any real number. However, in class today my professor...
CLIMATE REPORTS — Apr 09
Center of mass and moment of inertia of a $2$-dimensional donut?
I have a an assignment and I'm stuck on this question: First of all I can't figure out th...
BUSINESS NEWS — Apr 09
How can one "cancel out" set union as if I am using the additive property of equality of real numbers?
I am aware that for equalities involving, for instance involving real numbers, we have the cancellat...
REGIONAL UPDATES — Apr 09
Meaning of the spectral norm of a matrix
Is there an intuitive meaning for the spectral norm of a matrix? Why would an algorithm calculate th...
CELEBRITY BODYGUARDS — Apr 09
SageMath: defining class of functions on Elliptic Curves
In SageMath, I would like to manipulate rational functions on elliptic curves (defined on finite fie...
CELEBRITY FASHION LINES — Apr 09
Find sample size given standard deviation, sample mean, confidence interval
A machine is set up such that the average content of juice per bottle equals u. Assume that the popu...