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प्रश्न
If cosA + cos2A = 1, then sin2A + sin4A = 1.
विकल्प
True
False
उत्तर
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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Activity:
L.H.S = `square`
= (sin2A + cos2A) `(square)`
= `1 (square)` .....`[sin^2"A" + square = 1]`
= `square` – cos2A .....[sin2A = 1 – cos2A]
= `square`
= R.H.S
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