Question 711661
I have calculated this:

cos(-x)= -1/2
cos(x)= 1/2 ************ cos(-x) = cos(x)
x = ±120 degs ± n*360, n = 0,1,2,3...
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x=60 degrees + 2 pi Not a good idea to mix degs and radians.

Above answer is wrong, but what is wrong?

I would be happy if you help me find the right answer and show the calculation step by step so I know how to do it and see what I did wrong.

Thank you for helping me!