Question

How do i find the derivative of `(cos^2(x))/(1-sin^2(x))`?

Answer 1

The derivative of `f(x)/g(x)` would be (Quotient Rule):

`(f'(x)g(x)-f(x)g'(x))/[g(x)]^2`

But in your case:

`1-sin^2(x)=cos^2(x)`!!!!
So your function becomes: `(cos^2(x))/(cos^2(x))=1` with derivative equal to `0`!!!

(You can try with the quotient Rule and you'll get the same result!)