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Jun
20
answered How to prove that $\lim_{n\to\infty} \frac{1}{2}\tan(\frac{x}{2}) + … + (\frac{1}{2^{n}}) \tan(\frac{x}{2^{n}}) $ = $\frac{1}{x}-\cot(x)$
Mar
23
answered Prove that if $\alpha, \beta, \gamma$ are angles in triangle, then $(tan(\frac{\alpha}{2}))^2+(tan(\frac{\beta}{2}))^2+(tan(\frac{\gamma}{2}))^2\geq1$
Mar
23
answered Simple integral calculation: $\int \sqrt{x^2-4}\,dx$
Mar
18
answered Prove Trigonometric Identitiy
Mar
17
answered Why (x'Ay)^2 <=(x'Ax)(y'Ay), when A is positive definite?
Mar
11
answered Positive numbers inequality
Mar
11
answered Evaluating $\int_0^{\pi/2} \frac{a}{a^2+\cos^2 \theta} \, d\theta$
Mar
11
answered how to show $\frac{1+\cos x+\sin x}{1+\cos x-\sin x} = \frac{1+\sin x}{\cos x}$
Mar
11
answered Prove $(1 +\frac{ 1}{n}) ^ {n} \ge 2$
Feb
14
answered Divide By Vector
Feb
13
answered Evaluating $\lim_{n\to\infty}\small\left(\frac{1}{\sqrt{n}\sqrt{n+1}}+\frac{1}{\sqrt{n}\sqrt{n+2}}+\cdots+\frac{1}{\sqrt{n}\sqrt{n+n}}\right)$
Dec
6
answered How to prove that $A^2$ is a symmetric matrix
Nov
25
answered Efficient inversion of a symmetric, positive definite matrix
Nov
19
answered Prove $ A^-=\dfrac{1}{4}(-A^2+4A+I)$
Nov
19
answered show that $\mathsf E(Y|X)=\mu_2+\rho\dfrac{\sigma_2}{\sigma_1}(X-\mu_1)$
Nov
15
answered Jensen’s inequality
Nov
11
answered Why is this nested sum formula true
Oct
25
answered Prove $\int_0^{2\pi}\frac{3a\sin^2\theta}{(1-a\cos \theta)^4}$ or $\int_0^{2\pi}\frac{\cos\theta}{(1-a\cos\theta)^3}=\frac{3a\pi}{(1-a^2)^{5/2}}$
Sep
24
answered Is vector W in the span of V1,V2,V3
Sep
24
answered Subordinate norm is equal to $\Vert A\Vert_M=\Vert MAM^{-1}\Vert$ for the norm $\Vert x\Vert_M=\Vert Mx\Vert$