Question

Show that Sin(B+C/2) = CosA/2. if A , B , C are the angles of a triangle ABC.

Answer 1

Hi friend!!

The solution is given in the attachment.

I hope this will help you ;)

Answer 2

Hiii friend,

We know that the sum of the angles of a triangle is 180°

Therefore,

angle A + Angle B + Angle C = 180°

Angle B + Angle C = 180°-A

Then,

Angle B + Angle C/2 = 90°-A/2

Therefore,

Sin(B+C/2) = Sin(90°-A/2)

=> Sin(B+C/2) = Cos A/2 [ Sin(90°-theta) = cos theta]

Hence,

LHS = RHS

Sin (B+C/2) = CosA/2

HOPE IT WILL HELP YOU..... :-)