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| 1. |
Prove that sin^4x+cos^4x=1-2sin^2xcos^2x |
| Answer» To prove :\xa0sin4x\xa0+ cos4x = 1 - 2sin2x cos2xWe have,LHS = sin4x + cos4x= (sin2x)2 + (cos2x)2 + 2sin2x cos2x - 2 sin2x cos2x [By adding and subtracting 2sin2xcos2 x]= (sin2x + cos2x)2 - 2sin2x cos2x= 1 - 2sin2xcos2x\xa0= RHS | |