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visits member for 2 years, 4 months
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2h
reviewed Leave Closed What is integration contour and how to discribe it?
2h
reviewed Reopen Prove that if $B$ is diagonalzable then $A=0$
2h
reviewed Leave Closed What is linearity?
2h
reviewed Leave Closed Suppose that $\lim_{n \to \infty} x_n = x$ and that $|x_n - y_n| < \frac{1}{n}$ for all $n \in \Bbb{N}$. Prove that $\lim_{n \to \infty}y_n = x$
11h
revised Finding the eigenvalues of a given Markov matrix
putting the matrix in the title wastes space on the main page
2d
reviewed Leave Closed Does Mathematics exists apart from the mathematician?
Sep
27
awarded  Enlightened
Sep
27
awarded  Nice Answer
Sep
25
answered Mean value theorem for integrals: how does the sign matter?
Sep
25
revised Solving this summation: $\sum_{i=1}^k i\cdot2^i$
$$ in titles is wasteful
Sep
23
answered $\sum_{k=0}^n \binom{n}{k}^2 = \binom{2n}{n}?$
Sep
23
revised If $f(x)>0\;\forall x\in\mathbb{R},$ and $g(x)=f(x)+f'(x)+f''(x),$, Then prove that $g(x)>0\; \forall \; x\in \mathbb{R}$
added 399 characters in body
Sep
23
comment How to find this integral $I=\int_{-\pi}^{\pi}\frac{x\cdot \sin(x) \cot^{-1}{(2014^x)}}{1+\cos^4(x)}dx$
If you're really dead-set on using partial fractions, you could notice that $$\frac{8}{4+u^4}=\frac{2+u}{2+2u+u^2}+\frac{2-u}{2-2u+u^2}$$ and make the appropriate substitutions. karvens' solution is way nicer, though...
Sep
23
answered If $f(x)>0\;\forall x\in\mathbb{R},$ and $g(x)=f(x)+f'(x)+f''(x),$, Then prove that $g(x)>0\; \forall \; x\in \mathbb{R}$
Sep
22
comment How amount of Emirp Primes depends on the base of numeral system
@Asimov: I think the other commenters are right that you'd also expect a (smaller) effect based on digit sums. If $b-1$ has lots of prime divisors, you'd expect more emirps because, roughly speaking, you're squeezing the same number of primes into a smaller number of possible digit combinations. If you could properly account for that, it might remove some of the discrepancy (though obviously some of it is just going to be "random").
Sep
21
reviewed Leave Closed Fundamental group of some disk quotient
Sep
19
reviewed Leave Closed Basis of $\mathbf{Q}[x]$
Sep
19
revised Is Pythagoras the only relation to hold between $\cos$ and $\sin$?
added 2 characters in body
Sep
19
answered Is Pythagoras the only relation to hold between $\cos$ and $\sin$?
Sep
18
reviewed Reopen Simplifying an expression written as the sum of three fractions