1. Show that (coshx + sinhx)[to the power of] n = coshnx + sinhnx
This is trivial applying the definition of the hyperbolic functions
2. Determine the integral of tanhxdx
$\displaystyle \tanh x=\frac{e^x-e^{-x}}{e^x+e^{-x}}=\frac{e^{2x}-1}{e^{2x}+1}=1-\frac{2}{e^{2x}+1}$. Take it from here now (if you know integrals of usual trigonometric functions this one won't surprise you).
3. Determine the integral of 4dx/(e to the x + e to the -x)squared
[colo=blue]Get some ideas from the above
Tonio[/color]
PS How can i use the proper math symbols?!!
Using LaTex
Thanks!