Question

Integrate: $\int \sqrt{\frac{1-x}{1-x}}dx$

Answer 1

$\begin{array}{c}\int \sqrt{\frac{1-x}{1-x}}dx\\ =\int \frac{1-x}{\sqrt{1-x^2}}dx\\ ={\sin }^{-1}x+\sqrt{1-x^2}+C\end{array}$