Cos {B+C}\\2 = sin A\\2

1.	Cos {B+C}\\2 = sin A\\2
Answer» IN R.H.S apply cosA=sinA(90-A) Sorry multiply with cos in both side In R.H.S apply sinA=cosA(90-A) After that multiply with sin in both side Then take A to next side Then divide them all with 2 START with angle sum property of triangle..A+B+C =180°

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