Question

2 sin2A + cos 4A = 1+sin4A
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Answer 1

$2 {sin}^{2} A + {cos}^{4} A \\ = 2 {sin}^{2} A + ( { {cos}^{2}A })^{2} \\ = 2 {sin}^{2} A+ ( {1 - {sin}^{2} A})^{2} \\ = 2 {sin}^{2} A + 1 + {sin}^{4} A - 2 {sin}^{2} A \\ = 1 + {sin}^{4} A$