|

Analytical Geometry

Blazing goIITian

 Joined: 15 Aug 2008 Post: 584
17 Nov 2009 21:30:13 IST
0 People liked this
7
466
Engineering Entrance , JEE Main , JEE Advanced , Mathematics , Analytical Geometry

find the equation of circle whose diameter is common chord of circles x^2 + y^2 + 2x + 3y + 1=0  and

x^2 + y^2  +  4x + 3y + 2 =0

ans : -    2x ^2 + 2y^2 -2x -6y -1 =0

Hot goIITian

Joined: 2 Dec 2007
Posts: 101
17 Nov 2009 21:35:34 IST
0 people liked this

radical axis is the comman chord of the two circles... find the pt of intersection of radical axis and one of the circle then find the equation of circle by diameter form..

Blazing goIITian

Joined: 15 Aug 2008
Posts: 584
17 Nov 2009 21:37:21 IST
0 people liked this

Forum Expert
Joined: 19 Feb 2009
Posts: 1979
17 Nov 2009 21:39:28 IST
3 people liked this

Sorry for mistake bro!!!!!!!!!!!!!!!!

Hot goIITian

Joined: 2 Dec 2007
Posts: 101
17 Nov 2009 21:45:16 IST
0 people liked this

try by taking s3 = s1 + lamda l

Hot goIITian

Joined: 2 Dec 2007
Posts: 101
17 Nov 2009 21:45:42 IST
0 people liked this

l = comman chord

Blazing goIITian

Joined: 28 Oct 2009
Posts: 594
17 Nov 2009 23:43:11 IST
0 people liked this

hey bro may be i'm having u'r ans check out my photoalbum after few minutes

Forum Expert
Joined: 19 Feb 2009
Posts: 1979
18 Nov 2009 20:54:12 IST
1 people liked this

Center of the circl is  (-1,-3/2)  and (-2,-3/2)

Means The line passing through centre of both the circle can be written as y=-3/2

and this line will divide the chord in middle point whose y co-ordinate will be -3/2.

And since the eqution of chord is 2x+1=0

so x-cprdinate will be -1/2

So finally without hitting your mind you get the centre of the circle....as (-1/2 , -3/2)

Now to find the radius...simply apply pythagorus theorem....

Perpendicular distance from (-1.-3/2) to 2x+1=0

and radius of first circle...to find the half distance of chord whic is the radius of circle which we are trying to find.........

In anurag solution.......the two end points of chord which he has calculated........is right...and when you take the middle point of the two end point you will get the same point (-1/2.-3/2)

 Some HTML allowed. Keep your comments above the belt or risk having them deleted. Signup for a avatar to have your pictures show up by your comment If Members see a thread that violates the Posting Rules, bring it to the attention of the Moderator Team

## For Quick Info

Name

Mobile

E-mail

City

Class

Vertical Limit

Top Contributors
All Time This Month Last Week
1. Bipin Dubey
 Altitude - 16545 m Post - 7958
2. Himanshu
 Altitude - 10925 m Post - 3836
3. Hari Shankar
 Altitude - 9960 m Post - 2185
4. edison
 Altitude - 10815 m Post - 7797
5. Sagar Saxena
 Altitude - 8625 m Post - 8064
 Altitude - 6330 m Post - 1979

Physics

Topics

Mathematics

Chemistry

Biology

Institutes

Parents Corner

Board

Fun Zone