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

please give only hints in solving this integral

ireally dont know what to do first

:(

thanks

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- Aug 2nd 2007, 07:47 PM^_^Engineer_Adam^_^Trig integral:
$\displaystyle \int \frac{1}{5+4\sec{x}} dx$

please give only hints in solving this integral

ireally dont know what to do first

:(

thanks - Aug 2nd 2007, 08:08 PMcurvature
Try this substitution: u=tan(x/2)

- Aug 2nd 2007, 09:34 PM^_^Engineer_Adam^_^
whats the u here?

x = 2arctan(u)

dx = 2 ( 1/ (1 + u^2))

i dint understand still - Aug 3rd 2007, 01:24 AMtukeywilliams
$\displaystyle \sec x = \frac{(1+u^2)^2}{(1-u^2)^2} $

- Aug 3rd 2007, 01:33 AMcurvature
- Aug 3rd 2007, 02:45 AM^_^Engineer_Adam^_^
thanks!

oh yeahhh i forgot this was all easy using trig sub...

thanks a lot for the help