Computing special functions — I might have mentioned this once or twice before, but computers are essentially very stupid, since all they can do is add, subtract, multiply, divide and make simple yes/no decisions. Everything else a computer can...
Numerically inverting a matrix — Suppose you have a square matrix, like the one below: $$ A = \begin{pmatrix} 0 & 5 & 5 \\ 2 & 9 & 0 \\ 6 & 8 & 8 \end{pmatrix}, $$ and that...