![3cos^2x-sin^2x=sin2x\\-sin^2x-2sinx*cosx+3cos^2x=0\\sin^2x+2sinx*cosx-3cos^2x=0](https://tex.z-dn.net/?f=3cos%5E2x-sin%5E2x%3Dsin2x%5C%5C-sin%5E2x-2sinx%2Acosx%2B3cos%5E2x%3D0%5C%5Csin%5E2x%2B2sinx%2Acosx-3cos%5E2x%3D0)
Однородное уравнение 2-го порядка. Делим на cos^2x
![tg^2x+2tgx-3=0](https://tex.z-dn.net/?f=tg%5E2x%2B2tgx-3%3D0)
![tgx=t, t \neq \frac{\pi}2+\pi n; ne Z](https://tex.z-dn.net/?f=tgx%3Dt%2C+t+%5Cneq+%5Cfrac%7B%5Cpi%7D2%2B%5Cpi+n%3B+ne+Z)
![t^2+2t-3=0](https://tex.z-dn.net/?f=t%5E2%2B2t-3%3D0)
![D=4+12=16](https://tex.z-dn.net/?f=D%3D4%2B12%3D16)
![t_1=\frac{-2+4}2=1](https://tex.z-dn.net/?f=t_1%3D%5Cfrac%7B-2%2B4%7D2%3D1)
![t_2=\frac{-2-4}2=-3](https://tex.z-dn.net/?f=t_2%3D%5Cfrac%7B-2-4%7D2%3D-3)
Количество корней равно БЕСКОНЕЧНОСТИ.
"На отрезке? да принадлежащих отрезку [0;360]"
![\frac{\pi}4,\frac{5\pi}4,-arctg(3)+\pi,-arctg(3)+2\pi](https://tex.z-dn.net/?f=%5Cfrac%7B%5Cpi%7D4%2C%5Cfrac%7B5%5Cpi%7D4%2C-arctg%283%29%2B%5Cpi%2C-arctg%283%29%2B2%5Cpi)
pen = CreatePen(PS_SOLID, 1, RGB(100, 100, 100)); system_pen = (HPEN)SelectObject(hdc, pen); brush = CreateSolidBrush(RGB(100, 100, 100)); system_brush = (HBRUSH)SelectObject(hdc, brush);
Rectangle(hdc, x_square - 2, y_square - 2, x_square + 2, y_square + 2);
SelectObject(hdc, system_pen); SelectObject(hdc, system_brush); DeleteObject(system_pen); DeleteObject(system_brush);
x_square_old = x_square; y_square_old = y_square;
1)10:2/3=10/1×3/2=15
2)50:5/6=50/1×6/5=60
3)30:3/7=30/1×7/3=70