Question

A,B,C are interir anfles of triangle ABC sin(A+B)/2 + cos(A+B)/2 = cos c/2+sin c/2​

Answer 1

Answer:

A+b+c=180

A+b=180-c

Dividing with 2 on both sides

A+b/2=180-c/2

A+b/2=90-c/2

Applying sin on both sides

Sin(a+b/2)=sin(90-c/2)

Sin(a+b/2)=cos(c/2)