Prove cot(A) + cosec(A) = cot(A/2)
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show full solution
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cot(A) + cosec(A) = cot(A/2)
LHS
= cot(A) + cosec(A)
= [cos(A)/sin(A)] + 1/sin(A)
= [cos(A) + 1] / sin(A)
= [1+2cos²(A/2) - 1] / [2sin(A/2)cos(A/2)]
= [2cos²(A/2)] / [2sin(A/2)cos(A/2)]
= cos(A/2) / sin(A/2)
= cot (A/2)
= RHS
That's about it!
LHS
= cot(A) + cosec(A)
= [cos(A)/sin(A)] + 1/sin(A)
= [cos(A) + 1] / sin(A)
= [1+2cos²(A/2) - 1] / [2sin(A/2)cos(A/2)]
= [2cos²(A/2)] / [2sin(A/2)cos(A/2)]
= cos(A/2) / sin(A/2)
= cot (A/2)
= RHS
That's about it!