Q. 37. If $\int e^{x}\left\{c \cdot \log \left(x^{2}+1\right)+\frac{b x}{x^{2}+1}\right\} d x=\frac{b c}{2} e^{x} \cdot \log \left(x^{2}+1\right)$ then $(b, c)$ is

Solution:

Derivative of $\log \left(x^{2}+1\right)$ is $\frac{2 x}{x^{2}+1}$.
$\therefore \int e^{x}\left\{\log \left(x^{2}+1\right)+\frac{2 x}{x^{2}+1}\right\} d x$
$=e^{x} \cdot \log \left(x^{2}+1\right) $
$\therefore(b, c) \equiv(2,1)$