the 2 signals shown are used for modulating ( DSB-SC) a carrier with frequency fc. Now i need to find the similarities and differences between their time domain representation. Clearly the both will have same envelope. Now i tried for the difference part but could not find it. One possibility according to me can be the phase change at t=1. Can we find that what will be the phase change for both modulated signals at t =1 without drawing the actual plot ?