1. ## Trigonometric Integrals

While checking my works to my answers manual, I realized one of the steps I have a hard time understanding:

How did the integrals from pi/2 to 3pi/4 turn into 1 to rt2/2? I thought since u = sin x, doesn't x = pi/2 means that u = sin(3pi/4) = 1/rt2 instead of rt2/2?

2. rt2/2 is the same as 1/rt2

if that is what the question is? if not i blame it on being tired sorry

3. Oh, right, I remember now. Thanks!