Analytical Geometry

Madmax's Avatar
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20 Feb 2009 22:27:06 IST
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Line Question
Engineering Entrance , JEE Main , JEE Main & Advanced , Mathematics , Analytical Geometry

A st line passes thru A(-2,-3) and cuts line x+3y=9 and x+y+1=0 at B and C respectively. Find equation of the line if AB.AC=20

 

How do U go about this one??



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Sagar Saxena's Avatar

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20 Feb 2009 23:22:01 IST
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A st line passes thru A(-2,-3) and cuts line x+3y=9 and x+y+1=0 at B and C respectively. Find equation of the line if AB.AC=20

 

put the points in the given from

B   =  (-2+ r1 cos   ,-3 + r1 sin )

C =  (-2+ r2 cos   ,-3 + r2 sin )

where ::

r1  .  r2          = 20

from the above equation find the value of  where  is the slope of the line

guru  vignesh's Avatar

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21 Feb 2009 06:00:52 IST
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the answer is  Y-X+1=0


Cool goIITian

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18 Mar 2009 20:56:48 IST
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Try origin shift to A(-2,-3) then line passes throguh origin so y= mx form use origin shift on both line as well ;get the equation simplified in m as use AB.AC =20 get the equation ;shift it back after simplification; 




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