# Math Help - a few calc problems i need help with

1. ## a few calc problems i need help with

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

2. Originally Posted by bwong890
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)
[snip]
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).

Originally Posted by bwong890
[snip]
Find Integrals of:

(sec(x)^4)/(sqrt(tanx)) dx
Substitute $\sec^4 (x) = \sec^2 x \sec^2 x = (1 + \tan^2 x) \sec^2 x$ and then make the substitution $u = \tan x$.

If you need more help, please show all your work and say where you get stuck.