w = omega, just cant get it on.

ii) d2i/dt2 + 900i = A0 sin (wt)

Assuming that w2 not equal to 900, determine the current i in terms of the parameters (w and A0) and the variable t when the initial conditions are

i (0) = di/dt (0) = 0.

iii) Repeat part (ii) for w2 = 900

Help required people.