Question

solve this one fast .......​

Answer 1

sin(C +B )/2

Cos ( π/2 - (c +b)/2)

we know that

sum of angle of triangle = 180

so

A + B + C= 180

B + C = π - A

or

A = π - (B + C)

so

Cos ( π - (c+ b))/2

Cos (A/2)

Hence

LHS = RHS

proved

Answer 2

Answer:

Refer to the above attachment bro......