Zeroes of a Cos Function

[unborn grail]

Please help and explain how to find the answer

[latent carbon]

Bring the equation to an elementary form first:
2 - 4cos(x) = 0
4cos(x) = 2
cos(x) = 1/2
And now recall what solutions does cos(x) = a have.

[unborn grail]

Thank you

[potent beacon]

@unborn grail has given 1 rep to @latent carbon

[latent carbon]

You're welcome!

[unborn grail]

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