Question

The function $f(x)=\log (1+x)-\frac{2x}{2+x}$ is increasing on

• A. $(-\infty ,\infty )$
• B. $(-1,\infty )$
• C. $(\infty ,-1)$
• D. $(-\infty ,0)$

Answer 1

Answer: (B)

$f^{\prime }(x)=\frac{x^2}{(x+1)(2+x{)}^2}>0$
$x+1>0\Rightarrow x>-1$