Given cos^-1 x, where x ∈ [-1, 0]. Write its range.

The correct answer is Option (2) → $[\frac{\pi}{2}, \pi]$

$x\in [-1,0]$

We know:

• $\cos^{-1}(-1)=\pi$
• $\cos^{-1}(0)=\frac{\pi}{2}$

Also, $\cos^{-1}x$ is decreasing in its domain.

Therefore, the range is:$[\frac{\pi}{2}, \pi]$