What limit should I use to evalute the integeral?

Evaluate if and the surfaceSis given by for . (TakeSto have upward orientation.)

okay, so I integrate

with x = 0 to pi/16 and y = 0 to pi/16

and keep getting:

7.37119946071407E-05

I was wondering if I am using the right limits:

Please help........ (I am running out of tries!!)