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Vlad's user avatar
Vlad's user avatar
Vlad
  • Member for 9 years, 1 month
  • Last seen more than a month ago
  • California
26 votes
Accepted

How to prove that $e^x=\sum_{k=0}^\infty \frac{x^k}{k!}$?

12 votes
Accepted

What exactly IS a line integral?

11 votes
Accepted

Why is the norm convex?

10 votes
Accepted

Bound on the difference of two determinants

9 votes

Why I am getting different answer?

8 votes

Centre of the circle

7 votes
Accepted

Find the value of function at $\,x=5$

6 votes

How to solve $\frac{d^{2}y}{dx^2} + \frac{1}{x} \frac{dy }{dx} =0$?

5 votes
Accepted

What is so good about the $L^2$-norm of the second derivative being small?

5 votes
Accepted

Name of $|x|^p+|y|^p\le (|x|+|y|)^p$ ($p\ge 1$)?

5 votes

Integration of $e^{-x^2}$

5 votes
Accepted

Prove that the sphere is the only closed surface in $\mathbb{R}^3$ that minimizes the surface area to volume ratio.

5 votes
Accepted

partial derivative of a complex function.

5 votes

Why is $x_{1}^{2}+x_{2}^{2}+x_{3}^{2}+2\alpha {{x}_{1}}{{x}_{2}}>0$ for all $({{x}_{1}},{{x}_{2}},{{x}_{3}})\ne (0,0,0)$ if and only if $|\alpha |<1$?

4 votes
Accepted

PDE standard form chain rule derivations

4 votes
Accepted

Will all solutions of this ODE look like this?

4 votes
Accepted

Parallelepiped $P$ circumscribed around ellipsoid $S$: length of main diagonal of $P$ depends only on $S$, formula.

4 votes

Inner product equals for all vectors means

4 votes

How to prove $1 + 3 + 3^2 + ... + 3^{n-1} = (3^n - 1)/2$ by mathematical induction?

4 votes

Suppose I have some vector, how can I get a vector containing the nth order interaction terms of its elements?

4 votes

What is $0\div0\cdot0$?

3 votes
Accepted

Differentiating composition of functions proof help

3 votes
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Algebraic Aproach For this word problem

3 votes
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Is $\det(U_1\Lambda_1 U_1^t +U_2\Lambda_2 U_2^t +I)\le \det(\Lambda_1 +\Lambda_2 +I)$ correct?

3 votes

Distance between line and a point

3 votes

$e^{2\pi i x} = (e^{2\pi i})^x$: What happens if x is rational?

3 votes
Accepted

Solving the heat equation

3 votes
Accepted

The mysterious $\dot{H}^{-1}$ notation.

3 votes
Accepted

Showing that an equation of a curve in the plane defines a surface in $R^3$.

3 votes

Uniqueness, symmetry, and energy behavior for the diffusion equation on an interval

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