Question

sin (b+c/2)=cos A/2​

Answer 1

Given :- A + B + C = 90°

To prove :- sin ( B + C / 2 ) = cos ( A / 2 )

Salutation :-

A + B + C = 90°

Then , B + C = 90° - A ---------- ( i )

Therefore ,

sin ( B + C / 2 )

= sin ( 90° - A / 2 ). [ • Getting from no ----- ( i ) ]

= cos ( A / 2 ) [ As we know , sin( 90° - θ ) = cosθ , When θ is an acute angle ]

★ [ Hence Proved ] ★