Hi,

I'm solving the integral of sec x.

I'm using a t sub ie $\displaystyle t = tan(x/2)$

I've integrated to $\displaystyle ln(|1+t|/|1-t|)$

Now I believe I have to multiply inside the brackets by $\displaystyle cos(x/2)+sin(x/2)$ so I'll end up with

$\displaystyle (cos^2(x/2)+sin^2(x/2)+2cos(x/2)sin(x/2))/cos(x)$

Could someone explain that to me?

Thank You.