Standard parametric form:

The standard parametric form for particular unit circle is

x = cos θ          0 ≤θ ≤ 2π

y = sin θ

or         P (θ) = [x y] = [cos θ sin θ]  0 ≤ θ ≤ 2π

where the parameter θ is linked with the geometric angle measured counter clockwise from the positive x-axis. Equal enhancement in the parameter θ for the range 0 ≤ θ ≤ π/2 were utilized to obtain points on the arc illustrated in Figure (b). Since for this parametric representation, equal parameter enhancement generates equal arc length along the circumference of the circle, the appearance is fairly good.