Family of Circles

IMPORTANT

Family of Circles: Overview

This topic covers concepts, such as, Family of Circles, Family of Circles Passing through Two Given Points, Equation of Circum-circle of a Triangle with Given Sides & Equation of Circum-circle of a Quadrilateral with Given Sides etc.

Important Questions on Family of Circles

MEDIUM
IMPORTANT

The circle described on the chord x cosα+y sinα-p=0 of the circle x2+y2=a2 as diameter passes through the origin if

MEDIUM
IMPORTANT

If x+y=3 is the equation of the chord AB of the circle x2+y2-2x+4y-8=0, then the equation of the circle having AB as diameter is

EASY
IMPORTANT

Show that the equation of the circle described on the chord x cos α+y sin α=p of the circle x2+y2=a2 as diameter is x2+y2-a2-2p(x cos α+y sin α-p)=0.

HARD
IMPORTANT

The straight line x cos α+y sin α=p is intercepted by the circle x2+y2=a2 to form a chord of the circle. Taking this chord as a diameter, a circle is drawn. Prove that the equation of the circle drawn is x2+y2-2px cos α+y sin α=a2-2p2.

EASY
IMPORTANT

Center of the circle which passes through the point -2,2 and touches the circle x2+y2-6x+8y=0 at the point 0,0 will be

HARD
IMPORTANT

The radius of the circle touching the line x+y=4 at 1,3 and intersecting x2+y2=4 orthogonally is

HARD
IMPORTANT

If the diameter of first circle is the common chord for other circles having equation x2+y2+2x+3y+1=0 and x2+y2+4x+3y+2=0, then find the equation of first circle

HARD
IMPORTANT

Find the equation of the circle whose center lies on 3x+4y=7 and which passes through the points (1, -2) and (4, -3).

MEDIUM
IMPORTANT

If the circle x2+y2+6x+8y-5=0 is concentric with the circle x2+y2+2gx+2fy+c=0 on which the point (-3, 2) lies, then the value of c will be:

EASY
IMPORTANT

The coordinates of the two fixed points through which the circle x2+y2-2x+λx-1=0 passes are

HARD
IMPORTANT

Consider a family of circles passing through two fixed points A3,7 and B6,5. If the common chords of the circle x2+y2-4x-6y-3=0 and the members of the family of circles pass through a fixed point a,b, then

EASY
IMPORTANT

The equation to the circle which touches the axis of y at the origin and passes through 3, 4 is

HARD
IMPORTANT

Consider a family of circles passing through two fixed points A3,7 and B6,5. The chord in which the circle x2+y2-4x-6y-3=0 cuts each member of family of circles passes through a fixed point a,b. Then the value of a+3b is

EASY
IMPORTANT

The equation of the circles passing through 1, 2 and the points of intersection of the circles x2+y2-8x-6y+21=0    and x2+y2-2x-15=0 is

MEDIUM
IMPORTANT

If x-y+1=0 meets the circle x2+y2+y-1=0 at A and B then the equation of the circle with AB as diameter is

EASY
IMPORTANT

Find the equation of the circle through the point -2, 4 and through the points of intersection of the circle x2+y2+2x-4y-4=0 and the line 3x+2y-5=0

HARD
IMPORTANT

Equation of the circle, whose diameter is the chord x+y=1 of the circles x2+y2=4 , is -

MEDIUM
IMPORTANT

Equation of smallest circle passing through 'points of intersection of line x+y=1 & circle x2+y2=9

HARD
IMPORTANT

The P be the family of parabolas y=x2+px+q q 0 whose graphs cut the axes in three points. The family of circles through these three points have a common point

HARD
IMPORTANT

The equation of the circle whose diameter is the common chord of the circles x2+y2+2x+3y+2=0 and x2+y2+2x-3y- 4=0 is-