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InterviewSolution
| 1. |
If sinA +sin2A =1 ,prove that cos2A +cos4A =1 |
| Answer» Given that sinA + sin2A =1Then, sin A= 1 - sin2ATherefore, sin A = cos2A (since [1 - sin2A] is Cos2A by identity)Now substitute this in cos2A + cos4A = 1Instead of cos2A substitute (1-sin2A)Equating it, 1 - sin2A + cos4A = 1Now instead of sin A substitute cos2A , then sin2A = cos4A1- cos4A + Cos4A = 1. Cos4A gets striked outThus 1=1.Hence proved.... | |