Elena Schatz
Высший разум
(140700)
14 лет назад
1-cosx=sin(x/2)
1-(cos²(x/2)-sin²(x/2))-sin(x/2)=0
cos²(x/2)+sin²(x/2)-cos²(x/2)+sin²(x/2)-sin(x/2)=0
2sin²(x/2)-sin(x/2)=0
sin(x/2)(2sin(x/2)-1)=0
1)sin(x/2)=0⇒x/2=πn⇒x=2πn
2)2sin(x/2)-1=0⇒sin(x/2)=½⇒x/2=(-1)ᴷ•π/6+πk⇒x=(-1)ᴷπ/3+2πk,n∈Z,k∈Z.