public Fraction Tangent(LineFr that) // tan(theta) = (m1 - m2)/(1 + (m1*m2))
{
if (isParallelTo(that))
{
return(Fraction.Zero);
}
if (IsVertical())
{
if (that.IsHorizontal())
{
return(-1);
}
return(Slope.Inverse());
}
if (that.IsVertical())
{
if (that.IsHorizontal())
{
return(-1);
}
return(Slope);
}
if (isPerpendicularTo(that))
{
return(-1);
}
return((Slope - that.Slope) / (1 + Slope * that.Slope));
}
public LineFr PerpendicularLine(PointFr p)
{
if (IsHorizontal())
{
return(Vertical(p.X));
}
if (IsVertical())
{
return(Horizontal(p.Y));
}
var newSlope = Slope.Inverse();
return(new LineFr(newSlope, p));
}
