We know that sin-1x+ cos-1x = \(\cfrac{\pi}2\)
So, here y = sin–1 x + cos–1 x
= \(\cfrac{\pi}2\) which is a constant.
Also, sin-1 x and cos-1 x exist only when -1 ≤ x ≤ 1
So, \(\cfrac{dy}{d\mathrm x}
\) = 0 when x ∈ [-1, 1] and does not exist for all other values of x.