Question

Cos 2x - 2cos²x/sin²x​

Answer 1

Answer:

Remember Cos(A + B) = CosACosB - SinASinB

Now instead of B it is A

Cos(A + B) = CosACosB - SinASinB

Cos(A + A) = CosACosA- SinASinA

A + A can be simplified to 2A and CosA*CosA can become Cos^2A and the same for Sin

Cos(2A) = Cos^2A - Sin^2A

Hope it helps you

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