Question

If sin A + sin- A = 1, then the value of the
expression (cos? A + cos4 A) is:​

Answer 1

$\huge\fcolorbox{red}{gold}{αηѕωєя}$

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$sinA+sin2=1</p><p>sinA=1−sin2A</p><p>sinA=cos2A</p><p>Now cos2A+cos2A.cos2A</p><p>=sinA+sin2A</p><p>=1 ...(given)$

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