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1 Answer

+4 votes

Best answer

Answer is 1
Sin A + Sin^2 A = 1
Sin A = 1 - Sin^2 A
And we know 1 - Sin^2 A = Cos^2 A
so Sin A = Cos^2 A
squaring both side Sin^2 A = Cos^4 A
so
Cos^2 A + Cos^4 A = 1 from given condition