} // End Function Determinant2d
public MyPoint2D <T> Schnittpunktli(MyPoint2D <T> p1, MyPoint2D <T> p2, MyPoint2D <T> p3, MyPoint2D <T> p4)
{
T x1 = p1.X;
T x2 = p2.X;
T x3 = p3.X;
T x4 = p4.X;
T y1 = p1.Y;
T y2 = p2.Y;
T y3 = p3.Y;
T y4 = p4.Y;
T topaX = Determinant2d(x1, y1, x2, y2);
T topbX = Determinant2d(x1, Arithmetics <T> .ONE, x2, Arithmetics <T> .ONE);
T topcX = Determinant2d(x3, y3, x4, y4);
T topdX = Determinant2d(x3, Arithmetics <T> .ONE, x4, Arithmetics <T> .ONE);
T topX = Determinant2d(topaX, topbX, topcX, topdX);
T bottomaX = Determinant2d(x1, Arithmetics <T> .ONE, x2, Arithmetics <T> .ONE);
T bottombX = Determinant2d(y1, Arithmetics <T> .ONE, y2, Arithmetics <T> .ONE);
T bottomcX = Determinant2d(x3, Arithmetics <T> .ONE, x4, Arithmetics <T> .ONE);
T bottomdX = Determinant2d(y3, Arithmetics <T> .ONE, y4, Arithmetics <T> .ONE);
T bottomX = Determinant2d(bottomaX, bottombX, bottomcX, bottomdX);
T x = Arithmetics <T> .Divide(topX, bottomX);
T topaY = Determinant2d(x1, y1, x2, y2);
T topbY = Determinant2d(y1, Arithmetics <T> .ONE, y2, Arithmetics <T> .ONE);
T topcY = Determinant2d(x3, y3, x4, y4);
T topdY = Determinant2d(x3, Arithmetics <T> .ONE, y4, Arithmetics <T> .ONE);
T topY = Determinant2d(topaY, topbY, topcY, topdY);
T bottomaY = Determinant2d(x1, Arithmetics <T> .ONE, x2, Arithmetics <T> .ONE);
T bottombY = Determinant2d(y1, Arithmetics <T> .ONE, y2, Arithmetics <T> .ONE);
T bottomcY = Determinant2d(x3, Arithmetics <T> .ONE, x4, Arithmetics <T> .ONE);
T bottomdY = Determinant2d(y3, Arithmetics <T> .ONE, y4, Arithmetics <T> .ONE);
T bottomY = Determinant2d(bottomaY, bottombY, bottomcY, bottomdY);
T y = Arithmetics <T> .Divide(topY, bottomY);
// m = (y2-y1)/(x2-x1)
// Case 1: horizontal line: slope = 0 | y=constant, x=variable
// Case 2: vertical line: slope = +/-infinity | x=constant, y=variable
// Case 3: Parallel => m1 = m2
// Case 4: orthogonal resp. right-angle => m1 = -1/m2
return(new MyPoint2D <T>(x, y));
} // End Function Schnittpunktli
} // End function DotP
public static T Angle_Rad(MyVector2D <T> a, MyVector2D <T> b)
{
T axbx = Arithmetics <T> .Multiply(a.X, b.X);
T ayby = Arithmetics <T> .Multiply(a.Y, b.Y);
T azbz = Arithmetics <T> .ZERO;
T sumAB = Arithmetics <T> .Sum(axbx, ayby, azbz);
T ax2 = Arithmetics <T> .Pow(a.X, 2);
T ay2 = Arithmetics <T> .Pow(a.Y, 2);
T az2 = Arithmetics <T> .ZERO;
T bx2 = Arithmetics <T> .Pow(b.X, 2);
T by2 = Arithmetics <T> .Pow(b.Y, 2);
T bz2 = Arithmetics <T> .ZERO;
T aSquare = Arithmetics <T> .Sum(ax2, ay2, az2);
T bSquare = Arithmetics <T> .Sum(bx2, by2, bz2);
T val = Arithmetics <T> .Divide(sumAB,
(
Arithmetics <T> .Multiply(Arithmetics <T> .Sqrt(aSquare), Arithmetics <T> .Sqrt(bSquare))
)
);
T nReturnValue = Arithmetics <T> .Acos(val);
return(nReturnValue);
} // End function Angle_Rad