equation of circle Cartesian plane

Equation of circle Cartesian plane

The set of all points in the Cartesian plane that are equal distance from a fixed point is called a circle. The fixed point  is called the center of the circle, and the distance from the center of the circle to any point on the circle is called the radius of the circle.

equation-of-circle

If C(h, k) is the center of a circle, r its radius and p(x, y) any point on the circle is denoted by notation

Center of circle notation

Center of circle notation

By distance formula we get

Center of circle

\left ( x-h \right )^{2}+\left ( y-k \right )^{2}= r^{2}
Is an equation of circle in standard form

is an equation of the circle in standard form on the Cartesian plane.

Center of circle at origin

if the center of circle at origin, then equation of circle in standard form become.

Center of circle at origin
Center of circle at origin

Point  circle

if r =0, the circle is called point circle.

Which consist of the circle only.

Parametric equation of circle 

Let P(x, y) any point in the center of circle at origin

And let inclination of OP be θ (theta) in diagram

it is clear that

x= r cos θ

y= r sin θ

The point P (r cos θ, r sin θ) for all values of a theta (θ) are called parametric

equation of circle.

General form of an equation of circle on the Cartesian plane.

The equation

General form of an equation of circle
equation A  g, f, c are constant

represent a circle g, f, and c being constant.

This equation can be written in the form

(x^{2}+2gx+g^{2})+\left ( y^{2}+2fy+f^{2} \right )=g^{2}+f^{2}-c

after simplification

General form of an equation of circle on the Cartesian plane.

which is the standard form of an equation of a circle with center (-g, -f)

General form of an equation of circle on the Cartesian plane.
Equation of a circle with center (-g, -f) and radius

and radius

Thus, equation A is called the standard form of an equation of circle.

RELATED POST