Х² + 7х + 6 = 0
х1 + x2= -7
х1 × х2 = 6
х1 = -1
х2 = -6
х² + х = 56
х² + х - 56 = 0
х1 + х2 = -1
х1 × х2 = -56
х1 = -8
х2 = 7
3х² + 5х - 2 = 0
D = 25 - 4 × 3 × (-2) = √49 = 7
x1 = -5 + 7 / 2 × 3 = 2 / 6 = 1 / 3
x2 = -5 - 7 / 2 × 3 = -12 / 6 = -2
(-4/3)^2=16/9
----------------------------
Cos(arcsin 1) = cos π\4 = √2 \ 2
<span>1) не знаю, не пойму как преобразовать
2) 6<span>√2 / 2<span>√6 = 3<span>√2 / <span>√6 = 3<span>√2 * <span>√6 / 6 = 6<span>√3 / 6 = <span>√3</span> </span></span></span>
</span></span></span></span></span>
Sin(X)sin(2X)-sin(3X) - cos(X)cos(2X) = -(cos(X)cos(2X )- sin(X)sin(2X)) - sin(3X) = - cos(x+2x) - sin(3x) = -(sin3x + cos3x)