sin2x+2cos^2X=0
2sinxcosx+2cos^2x=0
2cosx(sinx+cosx)=0
x=П/2(2k+1)
sinx+cosx=0
tgx=-1
x=-П/4+Пk
sin2x+1=0 sin2x=-1 2x=-П/2+2Пk x=-П/4+Пk
sin4x-sin7x=0 -2sin3x/2cos11x/2=0
sin3x/2=0 3x/2=Пk x=2Пk/3
cos11x/2=0
11x/2=П/2(2k+1)
x=П/11(2k+1)
