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x in (-oo:+oo)
cos(2*x-(pi/4)) = 0
cos(2*x-(pi/4)) = 0 <=> 2*x-(pi/4) = pi*k_1+pi/2 i k_1 należy do I
t_1 = pi*k_1+pi/2
2*x-t_1-(pi/4) = 0
2*x-t_1-(pi/4) = 0 // + -t_1-(pi/4)
2*x = -(-t_1-(pi/4)) // : 2
x = (-(-t_1-(pi/4)))/2
x = (t_1+pi/4)/2
x = (pi*k_1+pi/2+pi/4)/2 i k_1 należy do I
x = (pi*k_1+pi/2+pi/4)/2
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