$\displaystyle \int SEC^4{5x} = \int ({SEC^2{5x}})({SEC^2{5x}})$

Then

$\displaystyle \int (1+TAN^2{5x})(SEC^2{5x})$

Then I multiply out

$\displaystyle \int (SEC^2{5x})+(SEC^2{5x}TAN^2{5x})$

I would assume U sub at this point

$\displaystyle U= SEC dU= SECTAN$

But I am not sure, what or how I should bring along with the SEC

Any help?

thanks

Rich