Question

Cos
20 = Cos²o - sm²o​

Answer 1

Answer:

please write your question correctly

Answer 2

hey buddy here is your answer

to prove---->cos2θ=Cos²θ - sin²θ ​​

As we know that cos(A+B)=cosA*cosB-sinA*sinB

           then cos2θ=cos(θ+θ)=cosθ*cosθ-sinθ*sinθ

                                              = Cos²θ - sin²θ ​​

hence cos2θ=Cos²θ - sin²θ

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