(sinx-cosx)^2-1=0 [0;2п]
sin^2x - 2sinxcosx + cos^2x - 1 = 0
1 - 2sinxcosx - 1 = 0
2sinxcosx=0
sin2x = 0
2 x=pik, k∈z
x = pik/2 , k∈z
+ОТБОР
0≤ pik/2 ≤2pi
0≤ (1/2)*k ≤ 2 /*2
0≤ k ≤ 4
k=0, 1, 2, 3, 4
k=0⇒ x=0
k=1⇒ x=pi/2
k=2⇒ x=pi
k=3⇒ x=3pi/2
k=4⇒ x=2pi
