Business Mathematics

CHAPTER 14

Circle

14.1  INTRODUCTION

A circle is the locus of a point which moves at a constant distance from a fixed point. The fixed point is called the center of the circle and the constant distance is called the radius of the circle.

A circle is completely determined if its center and radius are know n.

14.2  STANDARD FORM/GENERAL FORM/CENTER RADIUS FORM OF THE EQUATION OF A CIRCLE

To find the equation of the circle whose center is the point ( h, k ) and whose radius is r.

Let P(x,y ) be any point on the circle whose center is ( h, k) and radius is r.

We have CP = r.

By the distance formula,

 

CP² = (x − h )² + (y − k )²

Therefore,

 

(x − ...