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EDX's user avatar
EDX's user avatar
EDX
  • Member for 4 years
  • Last seen more than a month ago
5 votes
Accepted

Solve $6^{2x}-9^x=27$

5 votes
Accepted

Not sure about the limit of $\frac{\log(1+x^4)}{x^2 \tan^2(2x)}$ for $x$ that goes to zero

3 votes

Unitary matrix corruption

3 votes

Show that $\sum_{n=1}^{\infty}\ln(1+a_n)$ converges.

3 votes

$\lim_{(x,y)\to (0,0)}\frac{1-(\cos x)(\cos y)}{x^2+y^2} $

3 votes
Accepted

Coefficients of characteristic polynomial and eigenvalues

3 votes

Solving $\frac{dy}{dx}+3x^2y=6x^2$ using integrating factor

3 votes

$F(x , y)=\cos ^{y}\left(\frac{\pi}{x}\right)+\cos ^{y}\left(\frac{3 \pi}{x}\right)+\cos ^{y}\left(\frac{5 \pi}{x}\right)$

2 votes

How does the polynomial $X^{p-1}+1$ split over $\mathbb{F}_p$

2 votes

Find value of $p$ to make the series $\sum\limits_{n=1}^\infty\left(\dfrac1{n^p}\sum\limits_{k=1}^nk^{3/2}\right)$ converge

2 votes

$\alpha$ is unique if $f(x) \leq \alpha \leq g(x)$ for all $x$ and $\lim_{x\to a} ( g(x)-f(x)) = 0$

2 votes

Fix point of function over disk

2 votes
Accepted

The relation between $\ker(E)$ and the differential-algebraic equation $E\mathbf x'(t)=Ax(t)+f(t)$

2 votes

Find best approximation of $\sin(\pi x)$ over $[0,1]$ with quadratic polynomial $a_0+a_1x+a_2x^2$

2 votes

Integrate $\int_0^\infty \frac{\sin x}{x(1+x^2)^2} dx$ with contour integral

2 votes
Accepted

Why $(1 + \epsilon)^{k/2} \exp (-\epsilon)^{k/2} < \exp\left(-\frac{k}{2}(\epsilon^2/2-\epsilon^3/3)\right)$

2 votes

Find the sum of the expression below

2 votes

Square of the distance in three dimension space

2 votes
Accepted

$u_n(x)= \prod_{k=1}^{n} \big(1 +\frac{x}{n} f(\frac{k}{n}) \big)$ : asymptotic

2 votes

Find convex closure of certain set

2 votes

Using Cauchy product for an integral

2 votes
Accepted

Evaluate: $\sum_{k=0}^{n}(-4)^k\frac{{n+k \choose 2k}}{ak+b}$

2 votes

Show that $Z_t = \sqrt{\sqrt{2t}e^{-\sqrt{2t}}} B_{e^{\sqrt{2t}}-1}$ solves $dZ_t = f(t)Z_tdt +dM_t$ and find $f(t)$.

2 votes

Taylor series of $e^{-1/x}$

1 vote

Gradient, Hessian, and minimum of a vector function?

1 vote

What are the units of the variance/rate parameter in a 1D continuous Brownian diffusion process?

1 vote

Maximizing multinomial distribution with constraints using Lagrange multipliers

1 vote

Prove that $\sqrt{8}$ is irrational in different method

1 vote

Limsup of $\sin(rz)$ as $r\to \infty$

1 vote

Finding $\lim_{x\to0}\tan(x)^{1/x}$

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