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If sin A+ Sin^2 A=1, then find the value of the expression (cos^2 A+Cos^4A) |
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Answer» ong>ANSWER: Our starting GOAL is to turn all terms into cosine. Use the identity sin 2 θ + cos 2 θ = 1 . sin a + 1 − cos 2 a = 1
sin a − cos 2 a = 0
sin a = cos 2 a
SQUARE both sides to get RID of the sine. ( sin a ) 2 = ( cos 2 a ) 2
sin 2 a = cos 4 a
Reuse sin 2 θ + cos 2 θ = 1 : 1 − cos 2 a = cos 4 a
1 = cos 4 a + cos 2 a
HOPEFULLY this helps! |
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