thanks tonio and skeeter for helping me with the other problem.
heres more problems i need help with T.T
Find derivative of:
y = cos^-1(x+y)
y = tan^-1(x+y)
Find Integrals of:
(sec(x)^4)/(sqrt(tanx)) dx
Re-write as x = cos(y) - y and x = tan(y) - y and find dx/dy in the usual way. Then dy/dx = 1/(dx/dy).
Substitute $\displaystyle \sec^4 (x) = \sec^2 x \sec^2 x = (1 + \tan^2 x) \sec^2 x$ and then make the substitution $\displaystyle u = \tan x$.
If you need more help, please show all your work and say where you get stuck.