How do you integrate sec2(2x1)?

1 Answer
Jan 10, 2017

sec2(2x1)dx=12tan(2x1)+C

Explanation:

Note that ddxtan(x)=sec2(x). This implies that sec2(x)dx=tan(x)+C.

Apply the substitution u=2x1, which implies that du=2dx:

sec2(2x1)dx=12sec2(2x1)(2dx)=12sec2(u)du

As we saw before, sec2(u)du=tan(u)+C:

sec2(2x1)dx=12tan(u)+C

Returning to the original variable x, use u=2x1:

sec2(2x1)dx=12tan(2x1)+C