Argh I had a picture for this but don't have enough reputation for anything on here. I also don't understand how to insert the math notation in here.
If $f(x) = \int_0^{g(x)}(1+t^3)^{-\frac12} \mathrm{d}t$ where $g(x) = \int_0^{\cos x}(1+\sin (t^2))\mathrm{d}t$
I have to find $f'(\frac{\pi}{2}).$
I know it has something to do with substitution and I've tried integrating by parts and things like that too but its not working out. I think there is something about the way that the questions been asked thats not helping anyway that is the first question.
There'll be more in the future I'm sure.