If A, B,C are interior angles of a ΔABC, show that sec2(B+C2)−1=cot

1.	If A, B,C are interior angles of a ΔABC, show that sec2(B+C2)−1=cot2(A2) [3 MARKS]
Answer» If A, B,C are interior angles of a $Δ A B C$ , show that $s e c^{2} (\frac{B + C}{2}) - 1 = c o t^{2} (\frac{A}{2})$ [3 MARKS]

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