The initial value problem which describes the motion of a certain undamped harmonic oscillator isy" + 4y = 0, y(0) = 4, y'(0) = -6a) Solve the initial value problem.b) Express your solution in the...

The initial value problem which describes the motion of a certain undamped harmonic oscillator is y" + 4y = 0, y(0) = 4, y'(0) = -6 a) Solve the initial value problem. b) Express your solution in the form A cos(2x - d). Use the formula cos(A - B) = cos A cos B + sin A sin B c) What is the amplitude and period for this motion?