CUET Preparation Today
Which of the following functions is decreasing on $(0, \frac{\pi}{2})$? |
$\sin 2x$ $\tan x$ $\cos x$ $\cos 3x$ |
$\cos x$ |
The correct answer is Option (3) → $\cos x$ ## In the interval $(0, \frac{\pi}{2})$, $f(x) = \cos x$ $\Rightarrow f'(x) = -\sin x$ which gives $f'(x) < 0$ in $(0, \frac{\pi}{2})$. Hence, $f(x) = \cos x$ is decreasing in $(0, \frac{\pi}{2})$. |
