Is "1/12u" supposed to be "1/(12u)" or "(1/12)u"?

I will assume you meant "(1/12)u".

Please don't just write "=" like that. That means that what you are writing now is equal to what you had on the previous line. And that is not true.This is what I have:

sin^2(1/12u) = 1/2( 1 - cos( 1/6u))

sin^2(1/12u) = 1/2 -1/2 cos(1/6u) dx

= 1/12u-1/4sin(1/6) +c

Why "(1/12)u"? The anti-derivative of (1/2) is (1/2)u. How did you get the "1/4" in front of "cos((1/6)u"?I am lost, please help!