A particle is moving with acceleration a(t) = cos(t) + sin(t). Given that its position s
satises the initial conditions s(0) = 0 and s(pi/2)=2, find its position at time t =pi .
I know a(t) = f ''(t) =cos(t)+sin(t)
v(t) = f '(t) = sin(t) - cos(t) + C
s(t) = f (t) = -cos(t) - sin(t) +C +D
But what is C, and how to calculate it??