Question

sin b+c/2= cos a/2 proove​

Answer 1

Answer:

In triangle abc

Sum of angles of a triangle is 180°

a+b+c=180°

b+c=180-a

multiplying both side by 1/2

(b+c)/2=180°-a/2

(b+c)/2=90°-a/2

Taking L.H.S

Sin(b+c)/2

=Sin(90°-a/2)

=Cos a/2

=R.H.S

(proved)