a(t)=4sin3t;v(0)=1,s(0)=6
I'm trying to find expression for s(t). Should I wait till the end to add find and add constant. I got [1/9(13t-4sin(3t))+6] and it was wrong.
I get
d^2s/dt^2 = 4 sin 3 t
ds/dt = v = -(4/3)cos 3 t + c
when t = 0 , v = 1
1 = -4/3 + c
c = 7/3
v = -(4/3)cos 3 t + 7/3
s = -(4/9) sin 3 t + 7 t/3 + k
6 = k
s = (1/9)(21 t - 4 sin 3 t +54)