if A+B=C then prove that cos2A+cos2B + cos2C=1+2cosAcosB cosC Share with your friends Share 8 Shridhar Kaushik answered this Taking L.H.S., 18 View Full Answer Umashankar Sharma answered this sorry the question is like this-if A+B=C then prove that cos squareA+cos squareB + cos squareC=1+2cosAcosB cosC -5
