Question 970293
2cos^2(x) - 2sin^2(x) + 2 = 0
cos^2(x) - sin^2(x) + 1 = 0
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cos^2 + sin^2 = 1
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cos^2(x) - sin^2(x) + cos^2(x) + sin^2(x) = 0
2cos^2(x) = 0
cos(x) = 0
x = pi/2 ± n*pi, n = 0,1,2,3...