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प्रश्न
Prove that sin θ sin( 90° - θ) - cos θ cos( 90° - θ) = 0
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उत्तर
LHS = sin θ sin( 90° - θ) - cos θ cos( 90° - θ)
= sin θ . cos θ - cos θ . sin θ
= 0
= RHS
Hence proved.
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