Cos x + cos y the whole square + sin x minus sin y the whole square is equal to 4 cos square x + y divided 2
Answers
Answered by
4
Answer:
plzzz give me brainliest ans and plzzzz follow me
Attachments:
Answered by
8
Answer:
Step-by-step explanation:
(Cosx + Cosy)² + (Sinx + Siny)² = 4(Cos²((x - y)/2))
Step-by-step explanation:
prove that cos x + cos y whole square + sin x + sin y whole square equal to 4 cos square x minus y upon 2
(Cosx + Cosy)² + (Sinx + Siny)² = 4(Cos²((x - y)/2))
LHS
= Cos²x + Cos²y + 2CosxCosy + Sin²x + Sin²y + 2SinxSiny
= 1 + 1 + 2CosxCosy + 2SinxSiny
= 1 + 1 + 2(CosxCosy + SinxSiny )
= 2 + 2Cos(x -y)
= 2 ( 1 + cos(x-y))
= 2 ( 2Cos²((x-y)/2))
= 4Cos²((x-y)/2)
= RHS
(Cosx + Cosy)² + (Sinx + Siny)² = 4(Cos²((x - y)/2))
Similar questions