Verify if a point belongs to a line.
[c] = NL_F_LinePoint(a,b,x,y)
Slope.
y-intercept.
x-coordinate.
y-coordinate.
boolean.
NL_F_LinePoint verifies if the point of coordinates (x,y) belongs to the line defined by its slope a and its y-intercept b. If c=%T, the point belongs to the line. Else it does not.