Find dy/dx if. y = inverse of cos x

dy/dx = - 1 / √ (1 - x^2).

Step-by-step explanation:

y = arccos x.

So x = cos y

dx / dy = - sin y

dy / dx = - 1 / sin y

But sin y = √ (1 - cos^2 y)

But cos y = x, so cos^2y = x^2

Therefore

dy/dx = - 1 / √ (1 - x^2).