Integration of inverse trig functions

[bobsmith76]

Homework Statement

This is an integration of an inverse trig function.
I don't see how they go from 1/2 to 1/4. I understand how they get the 1/2, du = 2dx, divide both sides by 2, but where does the 1/4 come from?

 

[bobsmith76]

Ok, I've done some more research and looks like if anything the 1/2 should just be canceled out because you're supposed to put du in the numerator, which is 2 and 2 times .5 = 1.

 

[bobsmith76]

never mind, it looks like 1/4 but it's really 1/2. the book cut off the top part of 1/2 to make it look like 1/4. i found some guy on youtube doing the exact same problem.