Question

Please help me with this question

Answer 1

Answer:

Double Angle Identity for Cosine

Step-by-step explanation:

Using the double angle identity for cosine:

Cos2x = 2 cos^2x - 1

Answer 2

Answer:

○ double-angle identity for cosine

Step-by-step explanation:

Here is one the formulas:

2θ = 2cos²θ - 1

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