Q9 of 58 Page 8


Prove that: sin θ cos (90°- θ) + cos θ sin (90° - θ) = 1.


L.H.S = sin θ cos (90° - θ) + cos θ sin (90° - θ)
= sin θ sin θ + cos θ cos θ
= sin 2 θ + cos 2 θ

[Using Identity sin 2 φ + cos 2 φ = 1]

= 1
= R.H.S.

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