Question

If sinA + sin²A = 1, then the value of cos²A + cos⁴A is

-1

0

2

1

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Answer 1

${ \bold{ \huge {\mathfrak{Hello!}}}}$

$\bold{sin \theta + {sin}^{2} \theta = 1}$

$\longrightarrow \bold{sin \theta = 1 - {sin}^{2} \theta = {cos}^{2} \theta }$

Hance,

$\longrightarrow \bold{{cos}^{4} \theta = {sin}^{2} \theta}$

$\bold{adding} \\ {sin}^{2} \theta + {sin}^{4} \theta$

$\longrightarrow \: sin\theta + {sin}^{2} \theta$

$\longrightarrow 1$