If $0<a<1$ and $ A = \int_{0}^a \cos^{-1}x~\mathrm dx $, then $$\int_{-a}^a(\cos^{-1}x -\sin^{-1}\sqrt {1-x^2})~\mathrm dx =\pi a -\lambda A $$ Then find the value of $\lambda$
My doubt :
$\sin^{-1}\sqrt {1-x^2}=\cos^{-1}x $ if we write this then the value of requires integral will zero.
$\pi a-\lambda A =0 $.
Can anyone explain how to find the value of $\lambda$?