Question

hii please answer 13 question. ok 13 or question answer me ​

Answer 1

sent answer

this is the answer

Answer 2

Ang A + Ang B + Ang C = 180 (Angle sum prop of a triangle)

Ang B + Ang C = 180 - Ang A

(Ang B)/2 + ( Ang C )/2 = 90 -(Ang A)/2 (dividing both sides by 2)

Sin{(B + C)/2} = Sin { 90 - (A)/2}

[taking sin on both sides]

Sin {(B + C)/2} = Cos { A/2}

{Sin(90 - A) = Cos(A)}