Check wether the following equation are dimensionally correct.

(a) $\int \frac{d x}{\sqrt{a^{2}-x^{2}}}=\frac{1}{a} \sin ^{-1} \frac{a}{x}$, whenr $x$ and $a$ stand for distance.

(b) $f=\frac{1}{2 \pi} \frac{\sqrt{m g l}}{ I }$, where $I =$ Moment of Inertia