Question 437816
The 2 ways to write it shown make it 2 different problems.
If it's cosine squared, it's
4cos^2(2x) - 1 = 0
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cos^2(2x) = 1/4
cos(2x) = ± 1/2
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cos(2x) = +1/2
2x = 60 degs + n*360, n = 0,1,2,3...
x = 30 degs + n*180, n = 0,1,2,3...
2x = 300 degs + n*360, n = 0,1,2,3...
x = 150 degs + n*180, n = 0,1,2,3...
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cos(2x) = -1/2
2x = 120 degs + n*360, n = 0,1,2,3...
x = 60 + n*180, n = 0,1,2,3...
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2x = 240 degs + n*360, n = 0,1,2,3...
x = 120 + n*180, n = 0,1,2,3...