Problem :

i(t) = 10 sin(200 pi t)

Find q between t=0 s and t=0.01s

I know that it is a straightforward problem.

q=integration of i(t) from t=0 to t=0.01

The problem here is that the value of the integral equal zero!

q = 10 integration of ( sin(200 pi t) ) from t=0 to t=0.01

= ( - 10 / 200 pi ) [ cos(200 pi t) ] from t=0 to t=0.01

= ( -1 / 20 pi) [ cos( (200) (0.01) pi ) - cos(0) ]

Now the big problem is what is pi ?!!

is it 3.14 or 180 ?

Our T.A. said that if your calculator is in degrees, then pi=180

and if it is in radians, then pi = 3.14

My calculator is in degree, so i will put pi = 180

but this give me zero !

Any help?