# Math Help - Verifying derivatives?

1. ## Verifying derivatives?

Can someone please help me.. I'm having no luck with help at all I really appreciated if someone would kindly help me with this.

The inverse secant function is often defined for |x| ≥ 1
by y=sec^{ - 1}x <=> sec y = x , 0 ≤ y ≤ π , y ≠ π/2

Verify that the derivative is correct for x > 1

2. Verify that what derivative is correct? You haven't given us anything to verify.

If $y= f^{-1}(x)$ then $x= f(y)$ so that $\frac{df^{-1}(x)}{dx}= \frac{dy}{dx}= \frac{1}{\frac{dx}{dy}}= \frac{1}{\frac{df}{dy}}$

Take the reciprocal of whatever formula you are given for the derivative of inverse secant and see if it looks like the derivative of secant.