1. The problem statement, all variables and given/known data A mass of 4 kg is stretches a spring by 1 m. An external force of cos (!t) N acts on the mass. Assume that the damping constant is nonzero and gravity is 10 ms^-2. Consider a spring mass system described by the following IVP. u''+yu'+u = cos(wt) u(0) = 0 u'(0) = 0 1) Find the amplitude of the spring mass system in terms of w and y. 3. The attempt at a solution The solution says R2 = 1/((1-w2)2+w2y2) But how is that the solution, I can't find how to compute the amplitude in my textbook, it just says R2=A2+B2.