2cos<= \/3
Cosx<=\/3 / 2
Arccos a+2 Пn; 2П - arccos a + 2Пn
П/6+2Пn;11П/6 + 2Пn, n € z
(x²+x-20)(x²+x-2)=88
x²+x-2=a⇒x²+x-20=a-18
a(a-18)-88=0
a²-18a-88=0
a1+a2=18 U a1*a2=-88
a1=-4⇒x²+x-2=-4
x²+x+2=0
D=1-8=-7<0 нет решения
a2=22⇒x²+x-2=22
x²+x-24=0
D=1+96=97
x1=(-1-√97)/2 U x2=(-1+√97)/2
1/200√(200²*2)=√2
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Π=180°
1°=π/180°
1) 40 = 40°π/180° = 2π/9
2) 120° = 120°π/180° = 2π/3
3) 150° = 150°π/180° = 5π/6
4) 75° = 75°π/180° = 5π/12
5) 32° = 32°π/180° = 8π/45
6) 140° = 140°π/180° = 7π/9
Сначало упрощаем, а потом вставляем значения х
12х-27+8х+12у-30х+10у
-10х+22у-27
10х-22у+27
Если х=2, а у=-1, то 10*2-22*(-1)+27
20+22+27=69