Question:
The range of f(x) = cos [x], for π/2 < x < π/2 is
(a) {−1, 1, 0}
(b) {cos 1, cos 2, 1}
(c) {cos 1, −cos 1, 1}
(d) [−1, 1]
Solution:
(b) {cos 1, cos 2, 1}
Since, $f(x)=\cos [x]$, where $\frac{-\pi}{2}
$-\frac{\pi}{2}
$\Rightarrow-1.57
$\Rightarrow[x] \in\{-1,0,1,2\}$
Thus, $\cos [x]=\{\cos (-1), \cos 0, \cos 1, \cos 2\}$
Range of $f(x)=\{\cos 1,1, \cos 2\}$
Click here to get exam-ready with eSaral
For making your preparation journey smoother of JEE, NEET and Class 8 to 10, grab our app now.