1. ## Trig integral:

$\int \frac{1}{5+4\sec{x}} dx$

please give only hints in solving this integral
ireally dont know what to do first

thanks

2. Try this substitution: u=tan(x/2)

3. whats the u here?
x = 2arctan(u)
dx = 2 ( 1/ (1 + u^2))

i dint understand still

4. $\sec x = \frac{(1+u^2)^2}{(1-u^2)^2}$