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Question
Write the value of sin A cos (90° − A) + cos A sin (90° − A).
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Solution
We have,
`sin A cos(90°-A)=sin A sin A+cos A cos A`
= `sin^2 A+cos ^2 A`
We know that, `sin^2 A+cos ^2 A`
Therefore,
\[\sin A\cos\left( 90°- A \right) + \cos A\sin\left( 90°- A \right) = 1\]
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