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Question
Prove the following:
cosθ + sin (270° + θ) − sin (270° − θ) + cos (180° + θ) = 0
Solution
L.H.S. = cos θ + sin (270° + θ) − sin (270° − θ) +cos (180° + θ)
= cos θ + (− cos θ) − (− cos θ) − cos θ
= cos θ − cos θ + cos θ − cos θ
= 0
= R.H.S.
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