I forget math. Given a sine wave with offset 0, amplitude a, and frequency f (Hz), the area under a half cycle would be...
area = a * 0.637 * 0.5 / f
or simplified:
area = a / (Π * f)
... right? Because the area under a half cycle of a 1/2 hz wave would just be 1 * 0.637 (width * height of equivalent rectangle). Just want to double check. Thanks!
Why don't you check the calculation through a simple integral? You know the sine wave expression, you know the endpoints, so the definite integral would give you the right answer, irrespective of the simple formulae you're using :-D