x=5π/6
Объяснение:
2cos2x = -1
cos2x = -1/2 [0;π]
2x = ±π/3+2πk; k∈Ζ
x = ±π/6+πk; [0;π] k=1
x= -π/6+π=5π/6
x=5π/6
Объяснение:
2cos2x = -1
cos2x = -1/2 [0;π]
2x = ±π/3+2πk; k∈Ζ
x = ±π/6+πk; [0;π] k=1
x= -π/6+π=5π/6