Apparently, this user prefers to keep an air of mystery about them.
13 $\inf A = -\sup(-A)$ May 15 '13
2 Let $f$ be defined on $[a,b]$, Prove that if f has a local maximum at a point $x \in (a,b)$, and if $f'(x)$ exists, then $f'(x)=0$ May 16 '13
2 Suppose $f$ is a real-differentiable function on $[a,b]$ and suppose $f'(a)<c<f'(b)$. Prove then there is a point $x \in (a,b)$ such that $f'(x)=c$ May 16 '13
1 Suppose E is an infinite subset of a metric space X. May 10 '13