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vitamin d's user avatar
vitamin d's user avatar
vitamin d's user avatar
vitamin d
  • Member for 3 years, 4 months
  • Last seen this week
  • Zürich, Schweiz
14 votes
Accepted

Fastest way to find derivative of the function at the given point

9 votes
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Is the series $\sum_{n=1}^\infty \frac{3^n n^2}{n!}$ convergent

8 votes
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Why cant we apply the square root of a negative number to equate more imaginary numbers?

8 votes

Is $\curvearrowright$ a valid symbol for "implies that"?

6 votes
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How do I evaluate the limit $\;\lim\limits_{x\to 0}\dfrac{\sin3x}{x\cos2x}$?

6 votes

What is the name of the function $1/\Gamma(z) \int_0^\infty \frac{x^{z -1}}{e^w-1}dw$?

6 votes
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Solutions to $z^5-1=0$ using "root of unity"?

5 votes

Formula to get the exact number of primes below $n$

5 votes
Accepted

If $\int_1^\infty|f(x)|dx$ converges then $\int_1^\infty (f(x)\cos x)dx$ converges

5 votes

How to solve the differential equation: $y-xy'=\exp(y')$

5 votes
Accepted

If $F(a)=\int_0^1\frac{x^a-1}{\ln x}dx$ why $F'(a)=\frac1{a+1}$?

4 votes

How to evaluate $\lim\limits_{x\to 0}\frac{1-\cos 7x}{3x^2}$?

4 votes
Accepted

Is continuity characteristic required for two equations to be equal

4 votes
Accepted

Finding the inverse Laplace transform of $Y(s)=\frac{1-e^{-{\pi}s}}{(s^2+1)(s^2+4)}+\frac{s+1}{s^2+4}$

4 votes
Accepted

How do I construct polynomials with complex numbers?

4 votes

$\int_{[-a,a]} h(x) = \int_{[-a,a]} h(-x) ?$

4 votes
Accepted

How to use ratio test for the series $\frac{n}{2^n}$

4 votes

$\int \frac{\ln(1-\sin(2x))}{\sin(2x)}\, dx$

4 votes
Accepted

Source for closed form of sum $\sum_{n=0}^\infty\zeta(2+2n)x^{2n}$

4 votes

Delta function and $\sum_{t}\exp\{ i k t\} $

4 votes
Accepted

Pulling out a function from an integral. When is this allowed?

3 votes

Prove $ \int_{5\pi/36}^{7\pi/36} \ln (\cot t )dt +\int_{\pi/36}^{3\pi/36} \ln (\cot t )dt = \frac49G $

3 votes
Accepted

Calculate $\lim_{n \to \infty}\frac{a^n}{n!}$

3 votes
Accepted

Prove $F_n=(-1)^{n+1}F_{-n}$ without induction

3 votes

What is the solution of limit $\lim_{x\to\infty} \frac{x}{x} $?

3 votes
Accepted

How does $\frac{7}{\sqrt{{49-49x}}}$ simplify to $\frac{1}{\sqrt{{1-1x}}}$?

3 votes
Accepted

Are there any known infinite series of rational terms that are just irrational (not transcendental)?

3 votes

Does it make sense to talk about $ O(z)$ if $z$ complex?

3 votes

Asymptotic analysis: difference between big O and big Omega limits?

3 votes

Sokhotski–Plemelj theorem for the real line

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