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Analytical Geometry

Blazing goIITian

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17 Nov 2009 21:30:13 IST

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yagyadutt sir posted question plz answer ....please answer.....

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

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adi..

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17 Nov 2009 21:35:34 IST

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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..

jee-do or die

Blazing goIITian

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17 Nov 2009 21:37:21 IST

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@ adhithya lo ninu helida prakaara madidre answer barodila kanlo

Yagyadutt Mishra

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17 Nov 2009 21:39:28 IST

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

adi..

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17 Nov 2009 21:45:16 IST

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try by taking s3 = s1 + lamda l

adi..

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17 Nov 2009 21:45:42 IST

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l = comman chord

The wicked warrior ''Anurag the devil''

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17 Nov 2009 23:43:11 IST

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

Yagyadutt Mishra

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18 Nov 2009 20:54:12 IST

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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)

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