40 Why can't prime numbers satisfy the Pythagoras Theorem? That is, why can't a set of 3 prime numbers be a Pythagorean triplet? 27 Why is $e^\pi - \pi$ so close to $20$? 25 Why is the zero polynomial not assigned a degree? 23 Proving $x^{4}+x^{3}+x^{2}+x+1$ is always positive for real $x$ 13 Limit of $(\sum_{k=0}^{n}k^4)/n^5$

Reputation (25,827)

 +10 Prove variance in Uniform distribution (continuous) -2 Motivation for the Definition of Compact Sets -2 How can I show a supremum of a set is also its limit point? +10 Show that if G is a simple graph with at least 4 vertices and 2n-3 edges, it must have two cycles of the same length.

Questions (7)

 3 Convergence of powers of random variables 2 Inequality with moments $m(f^3) \le m(f^2) m(f)$ 2 Arithmetic mean of $L^2$ function is $L^2$ 2 Maximum principle easy proof 2 Variance of importance sampling estimator

Tags (284)

 277 real-analysis × 205 133 probability × 110 277 calculus × 170 125 elementary-number-theory × 34 203 linear-algebra × 117 111 integration × 71 172 sequences-and-series × 95 101 probability-theory × 67 139 limits × 87 99 matrices × 56