Okay everyone, I'm sure this is a simple fix but let's see if I'm on the right track:

We have been given a "project" to "prove" that the length of one complete arc of a cycloid generated by a circle of radiusa, equals the perimeter of a square that circumscribes the same circle. I know that the answer to my integral should be 8|a|, but it is not coming out that way. I know that I have made an error somewhere but I just can't seem to find it!

Assumeais a constant:

for

for

+

+

It's evident that I should not have a , instead I should have just 2 outside the integral. Right?