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Question
If cosA + cos2A = 1, then sin2A + sin4A = 1.
Options
True
False
Solution
This statement is True.
Explanation:
∵ cosA + cos2A = 1
⇒ cosA = 1 – cos2A = sin2A ...[∵ sin2A + cos2A = 1]
⇒ cos2A = sin4A
⇒ 1 – sin2A = sin4A ...[∵ cos2A = 1 – sin2A]
⇒ sin2A + sin4A = 1
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