sin(DAC)=CD/AC => CD=AC*Sin(DAC)
CD=3sin(37)
cos(DAC)=AD/AC => AD=cos(DAC)cos(37)
AD=3cos(37
s=CD*AD=(3sin(37)*3cos(37)
(x+2)(x²+x-12)>0
x²+x-12 = 0
D = 1+48 = 49 = 7²
x(1) = (-1+7) / 2 = 3
x(2) = (-1-7) / 2 = -4
(x+2)(x+4)(x-3)>0
- + - +
-----o-----o-----o------>x
-4 -2 3
x∈(-4; -2)U(3; +∞)
Решение смотри в приложении
X²-x=2x²-2x-3x+3
x²-x-2x²+2x+3x-3=0
-x²+4x-3=0
x²-4x+3=0
D=16-12=4
x1=(4+2)/2=3
x2=(4-2)/2=1