If a,b,c are the angel of triangle abc then prove that sin(b+c/2) = co

1.	If a,b,c are the angel of triangle abc then prove that sin(b+c/2) = cos a/2
Answer» Sin{(b+c)/2}=sin{(180-a)/2}=Sin(90-a/2)=cos a/2 a+b+c=180°. abc is a triangleb+c=180°-ataking rhssin(b+c/2)sin(180-a/2)sin(180/2-a/2)sin(90-a/2)cos(a/2)

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