Question:
Mark $(\sqrt{)}$ against the correct answer in each of the following:
$\int \cos ^{-1}\left(\frac{1-x^{2}}{1+x^{2}}\right) d x=?$
A. $2 x \tan ^{-1} x+\log \left(1+x^{2}\right)+C$
B. $-2 x \tan ^{-1} x-2 \log \left(1+x^{2}\right)+C$
C. $2 x \tan ^{-1} x-\log \left(1+x^{2}\right)+C$
D. none of these
Solution:
