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Question
Prove that `(cos(90 - "A"))/(sin "A") = (sin(90 - "A"))/(cos "A")`
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Solution
L.H.S = `(cos(90 - "A"))/(sin "A")`
= `"sin A"/"sin A"`
= 1
R.H.S = `(sin(90 - "A"))/(cos "A")`
= `"cos A"/"cos A"`
= 1
∴ L.H.S = R.H.S
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