cos π(2x-3)/3 = 1/2
π(2x-3)/3 = π/3 + 2πn n∈Z
π(2x-3)/3 = -π/3 + 2πk k∈Z
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(2x-3)/3 = 1/3 + 2n
(2x-3)/3 = -1/3 + 2k
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(2x-3) = 1 + 6n
(2x-3) = -1 + 6k
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2x=4 + 6n
2x= 2 + 6k
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x=2 + 3n
x=1 + 3k
