Question

Plz answer the 16th question

83deb663539133ddb899b5064ef1de62.pdf

Answer 1

Step-by-step explanation:

Given-----> Sinθ = a / ( b + c )

To prove -----> Cosθ = 2 √bc CosA/2 / ( b + c )

Solution----->

1) Plzzz see the attachment

2) First we find value of cosθ , we know that ,

Sin²θ + Cos²θ = 1

=> Cos²θ = 1 - Sin²θ

=> Cosθ = √( 1 - Sin²θ )

Putting Sinθ = a / ( b + c ) then , and using

2S = a + b + c and

Cos A / 2 = √ { s ( s - a ) } / bc we proved required result .