Discussion

Question:

If $f (x) = \log (\frac{1 + x}{1 - x}),$ then f(x) + f(y) =

Explanation:

$f (x) + f (y) = \log (\frac{1 + x}{1 - x}) + \log (\frac{1 + y}{1 - y}) = \log \frac{(1 + x) (1 + y)}{(1 - x) (1 - y)} = \log \frac{1 + x y + x + y}{1 + x y - (x + y)} = \log \frac{1 + \frac{x + y}{1 + x y}}{1 - \frac{x + y}{1 + x y}} = f (\frac{x + y}{1 + x y})$

Hence, option (d).

» Your doubt will be displayed only after approval.

Doubts

Feedback