A circle is the locus of points that moves in a plane such that its distance from a fixed point is always constant. The fixed point is called the ‘centre’ while the fixed distance is called the ‘radius’.
Parametric equation of circle
A parametric equation of a circle is the coordinates of a point on the circle in terms of a single variable. These single variables are called as parameter.
Equation of circle = x2 + y2 = r2
X = r cos
Y = r sin
Squaring both side
x2 + y2 = (r2 cos Ɵ + r2 sin2Ɵ)
= r2 (cos2 Ɵ + sin2 Ɵ)
x2 + y2 = r2