Question

-1 +Sina sin(90-A)/cot(90-A) =-sinA sq

Answer 1

Lhs

= -1 +Sina sin(90-A)/cot(90-A)
=-1+Sin a. Cosa /tan A
=-1 +sina. Cos a. Cos a/sina
=-1+cos^2 a
=cos^2 a-1
= - (1-cos^2 a)
=-sin^2 a

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