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Poseidaan
  • Member for 4 years, 8 months
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4 votes
Accepted

For $J=\{1,2,\dots,n \}$ is there an easy way to compute $\prod\limits_{i\in J | i \ne k} (k-i)$?

3 votes

$\|Ax - By\| \leq c \|x-y\|$ for some constant $c$

0 votes

Does the idea of creating a perfectly random problem to solve this have any merit, or is it completely useless quackery?

1 vote

Volume integral of the gradient of a scalar field.

1 vote

Find normal of a point and determine if another point is to the same side of the normal

1 vote

Expressing $\frac{x-y}{w-z}$ as a function of $\frac{x}{w}$ and $\frac{y}{z}$

0 votes

Is the set $A = \{1,1/2,1/3,\ldots,1/n,\ldots\}$ open or closed

2 votes

Why does $\sum_{k=0}^{n} (-1)^k {n \choose k} = 0$ if $n\neq 0$ and 1 otherwise?

0 votes
Accepted

Does there exist a function $f(x)$ such that $f'(x)$ exists for all $x \in A$ but $f'(x)$ is not continuous on $A$?

1 vote
Accepted

Given $f(x) = \int_{0}^{x^{20}}{\sqrt{t}\sin{\sqrt{t}}\,dt}$. Find $f^{(80)}(0)$

1 vote

Proof using the converse.

1 vote

If $f(nx)=f(x)^n$ then $f(x+y)=f(x)f(y)$