An AM cosine wave is represented by x(t)=12+7*sin(pi*t-(1/3)*pi)]*cos(13*pi*t). Use phasors to show that x(t) can be expressed in form of: A1cos(w1*t+phi1) + A2cos(w2*t+phi2)+A3cos(w3*t+phi3) where w1<w2<w3. I am really stuck with this. dont know where to start. can someone please help me out???