Equation of Circle

IMPORTANT

Equation of Circle: Overview

This topic covers concepts, such as, Circle, Equation of Circle, Equation of Circle in Diameter Form & Equation of Circle in Parametric Form etc.

Important Questions on Equation of Circle

HARD
IMPORTANT

Tangents drawn from the point P(1, 8) to the circle 

x2+y2-6x-4y-11=0

touch the circle at the points A and B. The equation of the circumcircle of the triangle PAB is

HARD
IMPORTANT

Extremities of a diagonal of a rectangle are 0, 0 and 4, 3. Find the equation of the tangents to the circumcircle of a rectangle which are parallel to this diagonal.

HARD
IMPORTANT

The circle Cx2+y2+kx+1+ky-k+1=0 passes through two fixed points for every real number K. The minimum value of the radius of circle C is

HARD
IMPORTANT

If a circle passes through the points of intersection of the coordinate axes with the lines   λxy+1=0andx2y+3=0 , then the value of   λ is:

EASY
IMPORTANT

If A and B are fixed points in the plane such that PA PB =k  (constant) for all P on a given circle, then the value of k cannot be equal to:

MEDIUM
IMPORTANT

The equation of a circle with centre on y-axis and passing through the origin and the point (3, 4) is

HARD
IMPORTANT

The number of integer values of k for which the equation x2+y2+k-1x-ky+5=0 represents a circle whose radius cannot exceed 3, is

MEDIUM
IMPORTANT

Let C be the circle whose diameter is the line segment formed by the line 3x+2y=6 intercepted by the coordinate axes. Then C also passes through the point.

HARD
IMPORTANT

Consider a family of circles which are passing through the point -1,1 and are tangent to  x-axis. If h,k are the coordinate of the centre of the circles, then the set of values of k is given by the interval

MEDIUM
IMPORTANT

If the abscissa and ordinates of two points P and Q are roots of the equations x2+2ax-b2=0 and y2+2py-q2=0 respectivaly, then the equation of the circle with PQ as diameter, is

HARD
IMPORTANT

The other end of the diameter through the point -1, 1 on the circle x2+y2-6x+4y-12=0 is

EASY
IMPORTANT

The area of the circle x2-2x+y2-10y+k=0 is 25π. The value of k is equal to

MEDIUM
IMPORTANT

Centre of circle whose normals are x2-2xy-3x+6y=0, is

MEDIUM
IMPORTANT

Let A1,2, B3,4 be two points and Cx,y be a point such that area of ABC is 3 sq. units and x-1x-3+y-2y-4=0. Then number of positions of C, in the xy plane, is 

EASY
IMPORTANT

The equation of the circle concentric with the circle x2+y2-6x-4y-12=0 and touching Y-axis

EASY
IMPORTANT

If the equation px2+2-qxy+3y2-6qx+30y+6=0 represents a circle, then the value of p+q.

MEDIUM
IMPORTANT

The equation of the circle concentric with the circle x2+y2-6x-4y-12=0 and touching Y-axis

HARD
IMPORTANT

A circle passes through the points 2,3 and 4,5. If its centre lies on the line, y-4x+3=0, then its radius is equal to :

MEDIUM
IMPORTANT

The equation of the circle of radius 3 that lies in the fourth quadrant and touching the lines x=0 and y=0 is

EASY
IMPORTANT

The centre of the circle x=2+3cosθ, y=3sinθ-1 is