Evaluate $\displaystyle\int\frac1{\sqrt{9-x^2}}\,\mathrm dx$ for $|x|

Question

Evaluate $\displaystyle\int\frac1{\sqrt{9-x^2}}\,\mathrm dx$ for $|x|<3$.

Accepted Answer

$\arcsin(x/3)+C$

Arc sine antiderivative with a linear input