Question

If cos Θ = -0.1, find the value of cos (Θ + 2π) + cos(Θ + 4π).

Answer 1

cos(Θ + 2π) + cos(Θ + 4π) = -0.2

Explanation:

The cosine funciton is periodic with period 2π, so we have ...

cos(Θ) = cos(Θ + 2π) = cos(Θ + 4π) = -0.1

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The sum is ...

cos (Θ + 2π) + cos(Θ + 4π) = -0.1 +(-0.1) = -0.2