Browse Questions

The function $f(x)=x^{2}$ is decreasing in

$\begin{array}{1 1}(1)(-\infty ,\infty)&(2)(-\infty ,0 )\\(3)(0 , \infty)&(4)(-2 ,\infty)\end{array}$

$f(x)=x^2$
$f'(x)=2x$
$f'(x) < 0\;if\; x <0$
$\therefore$ f(x) is decreasing in $(\infty,0)$
Hence 2 is the correct answer.