Sin4 + Cos4 = 1 - 2Sin2Cos2 Share with your friends Share 0 Gursheen kaur. answered this 9 View Full Answer Sandeep Kumar answered this sin4A + cos4A = 1 - 2sin2Acos2A=sin4A + cos4A + 2sin2Acos2A = 1LHS = sin4A + cos4A + 2sin2Acos2A =(sin2A + cos2A)2 =12 =1 = RHS please thumbs up -2