1. ## Finding the derivative

$Cos x= e^y$
0<x<pi/2
What is dy/dx in terms of x?
Thanks!

2. Originally Posted by Linnus
$Cos x= e^y$
0<x<pi/2
What is dy/dx in terms of x?
Thanks!
you may be thinking about differentiating implicitly, but it is possible to solve for y here

$\cos x = e^y \implies y = \ln ( \cos x)$

now, can you differentiate that? Hint: use the chain rule

3. ah, thanks, i can't believe I overlooked that