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Question
If A, B, C are the interior angles of a triangle ABC, prove that
`tan ((C+A)/2) = cot B/2`
Solution
We have to prove: `tan((C + A)/2) = cot B/2`
Since we know that in triangle ABC
A + B + C = 180
`=> C + A = 180^@ - B`
`=> (C + A)/2 = 90^@ - B/2`
`=> tan (C + A)/2 = tan (90^@ - B/2)`
`=> tan (C + A)/2 = cot B/2`
Proved
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