18+5x=3*11
18+5x=33
5x=33-18
5x=15
x=15:5
x=3
Сам думай !.....................................................................
<span>√3·sin2X+cos2X+1=0</span>
<span>2√3·sinxcosx+ cos^2x-sin^2x+sin^2x+ cos^2x=0</span>
<span>2√3·sinxcosx+2cos^2x=0</span>
cosx(2√3·sinx+cosx)=0
cosx=0 или √3·sinx+cosx=0 / cosx
x=п/2+пn cosx cosx
√3tgx +1=0
√3tgx=-1
tgx=-1/√3
x=п/6+пn
ответ: п/2+пn
п/6+пn