Find the equation of circle concentric with the circle x^2 + y^2 + 4x – 2y + 4 = 0 and 3 times its radius 

Dear Student,
Please find below the solution to the asked query:


‚ÄčWe have:x2+y2+4x-2y-4=0Center of this cirlce=-42,--22=-2,1As required cirlce is concentric with above cirlce hence centre of required circlewill also be -2,1Let equation of required cirlce be:x-h2+y-k2=r2, where h,k is centre and 'r' is radius.x+22+y-12=r2Radius of x2+y2+2gx+2fy+c=0 is g2+f2-cHence radius of given circle x2+y2+4x-2y-4=0 is:R=22+-12--4=4+1+4=3Radius of required cirlce r=3R=3×3=9Hence required equation of circle is:x+22+y-12=92x+22+y-12=81

Hope this information will clear your doubts about this topic.

If you have any doubts just ask here on the ask and answer forum and our experts will try to help you out as soon as possible.
Regards

  • 1
What are you looking for?