Строка "а"
80,40,40,30,8,0
строка "в"
20,20,10,10,1,5
строка "а*в"
1600,800,400,300,8,0
строка "а:в"
4,2,4,3,8,0
4y+2y-y=20
5y=20
y=4
7y+y-2y=24
6y=24
y=4
![y= \int {(sin2x-6cos^2x*sinx)} \, dx = \int {sin2x} \, dx -\int {6cos^2x*sinx} \, dx = \\ = \frac{1}{2} \int {sin2x} \, d2x +6\int {cos^2x} \, dcosx = -\frac{1}{2} cos2x+6* \frac{1}{3}cos^3x+C = \\ =2cos^3x- \frac{1}{2} cos2x+C](https://tex.z-dn.net/?f=y%3D+%5Cint+%7B%28sin2x-6cos%5E2x%2Asinx%29%7D+%5C%2C+dx+%3D+%5Cint+%7Bsin2x%7D+%5C%2C+dx++-%5Cint+%7B6cos%5E2x%2Asinx%7D+%5C%2C+dx+%3D+%5C%5C+%3D+%5Cfrac%7B1%7D%7B2%7D++%5Cint+%7Bsin2x%7D+%5C%2C+d2x++%2B6%5Cint+%7Bcos%5E2x%7D+%5C%2C+dcosx+%3D+-%5Cfrac%7B1%7D%7B2%7D+cos2x%2B6%2A+%5Cfrac%7B1%7D%7B3%7Dcos%5E3x%2BC+%3D+%5C%5C+%3D2cos%5E3x-+%5Cfrac%7B1%7D%7B2%7D+cos2x%2BC)
y(π/2)=2cos³(π/2) -(1/2)cosπ +C
2cos³(π/2) -(1/2)cosπ +C=3/2
0+1/2+C=3/2
C=1
y=2cos³x -(1/2)cos2x +1
Чтобы избавиться от модуля, необходимо возвестив квадрат:
(x-2)²=6²
x²-4x+4=36
x²-4x+4-36=0
x²-4x-32=0
по т.Виетта:
![\left \{ {{b=-( x_{1} + x_{2}) } \atop {c= x_{1} x_{2} }} \right.](https://tex.z-dn.net/?f=+%5Cleft+%5C%7B+%7B%7Bb%3D-%28+x_%7B1%7D+%2B+x_%7B2%7D%29+%7D+%5Catop+%7Bc%3D+x_%7B1%7D++x_%7B2%7D+%7D%7D+%5Cright.+)
![\left \{ {{-4=-( x_{1} + x_{2}) } \atop {-32= x_{1} x_{2} }} \right.](https://tex.z-dn.net/?f=+%5Cleft+%5C%7B+%7B%7B-4%3D-%28+x_%7B1%7D+%2B+x_%7B2%7D%29+%7D+%5Catop+%7B-32%3D+x_%7B1%7D++x_%7B2%7D+%7D%7D+%5Cright.+)
![\left \{ {{ x_{1} =8} \atop { x_{2} =-4}} \right.](https://tex.z-dn.net/?f=++%5Cleft+%5C%7B+%7B%7B+x_%7B1%7D+%3D8%7D+%5Catop+%7B+x_%7B2%7D+%3D-4%7D%7D+%5Cright.+)
88 га = 0.88 км^2
8800/0.88=10000
8800 км^2 больше, чем 88 га в 10000 раз