Niron
6 год назад
2cos^2 x/4-2sin^2 x/4 = -1 решить уравнение
ОТВЕТЫ
Ермолай
Jul 6, 2019
2cos^2 x/4 -2sin^2x/4= -1,
2(cos^2 x/4 - sin^2 x/4)= -1,
(cos^2 x/4 - sin^2 x/4) = -1/2,
cos(2(x/4))= -1/2, cos(x/2)= -1/2,
x/2=+-2π/3+2πk, k∈Z,
x=+-4π/3 +4πk, k∈Z
2(cos^2 x/4 - sin^2 x/4)= -1,
(cos^2 x/4 - sin^2 x/4) = -1/2,
cos(2(x/4))= -1/2, cos(x/2)= -1/2,
x/2=+-2π/3+2πk, k∈Z,
x=+-4π/3 +4πk, k∈Z
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