Question

Find dy/dx if. y = inverse of cos x​

Answer 1

dy/dx = -1 /√(1 - x^2).

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).