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Question
Prove that:
`(cos(90^circ - theta)costheta)/cottheta = 1 - cos^2theta`
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Solution
L.H.S. = `(cos(90^circ - theta)costheta)/cottheta`
= `(sinthetacostheta)/(costheta/sintheta)`
= `(sinthetacostheta xx sintheta)/costheta`
= sin2θ
= 1 – cos2θ = R.H.S.
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