6,9-10+7,94y=1+6,9-2,06y
7,94y+2,06y=1+6,9-6,9+10
10y=11
у=1,1
Ответ:1,1
Sin57cos27+cos57sin27= sin(57 + 27) = sin(84) ≈ 0.99
sin57cos27-cos57sin27= sin(57 - 27) = sin(30) = 1/2
2sin 75*cos75= sin2*75 = sin150 = sin(180 - 30) = sin30 = 1/2
2sin 75 - cos75 = 2si + 45) – cos(30 + 45) = 2sin30cos45 + 2cos30sin45 – cos30cos45 + sin30sin45 = 2*(1/2)*(√2/2) + 2*(√3/2)*(√2/2) - (√3/2)*(√2/2) + (1/2)* (√2/2) = 3√2/4<span> - √6/4</span>
1)
д=36-4×8=4
х1=(-6-2)/2=-4
х2=(-6+2)/2=-2
2)
х-6=0
х1=6
49+х^2=0
х^2=-49 корней нет
3)
х^3-169х=0
х(х^2-169)=0
х1=0
х^2-169=0
х^2=169
х2=-13
х3=13
4)
х^2-4х+4-12=0
х^2-4х-8=0
д=16-4×(-8)=48
х1=(4-!/48)/2=(4-4!/3)/2=2-2!/3
!/ знак корня
х2=2+2!/3
5)
д=100-4×25×1=0
у=-10/(2×25)=-1/5=-0.2
6)
д=1-4×(-30)=121
х1=(-1-11)/2=-6
х2=(-1+11)/2=5
5(2cos²x-1)-2cosx-3=0 10cos²x-2cosx-8=0 Замена а=cosx, 10а²-2а-8=0 5а²-а-4=0 D=1+80=9² a1=(1-9)/20=-8/20=-2/5=-0.4 a2=(1+9)/20=1/2 x=±arccos(-0.4)+2πn, n∈Z; x=±π/3+2πn, n∈Z;