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doubt on GPEP qs

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doubt on GPEP qs

by anjaligeorge1 » Thu Jun 05, 2008 8:39 pm
A certain circle in the xy-plane has radius of 2 and has its center at the origin. If line L is tangent with the circle, what is the slope of the circle?
(1) L passes through point (0, 2).
(2) L passes through point (3, 2).
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by niksdoon » Fri May 07, 2010 12:49 pm
Is the OA -> B. Pls confirm and will try to explain.
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by moliver » Fri May 07, 2010 1:04 pm
IOA = D
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by debmalya_dutta » Fri May 07, 2010 4:45 pm
radius = 2 and
center at (0,0).
line L is tangent with the circle

(2) L passes through point (3, 2). => insufficient because there can be 2 tangential lines drawn from (3, 2)

(1) L passes through point (0, 2). => the circle with radius 2 will intersect at (0,2), Since L is tangent at 0,2 , it means that the tangent L is parallel to x axis. Hence the L's slope can be determined

Answer - Option A
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by 2011mbaspirant » Fri May 07, 2010 4:47 pm
IMO the answer is A. There is only one way the tangent can pass through point (0,2). However, from point (3,2) there are two ways in which a tangent can be drawn giving us two values of the slope instead of one definite answer.
Please correct me if I am wrong.
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by ansumania » Sat May 08, 2010 9:52 am
wat is the OA?
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by harshavardhanc » Sat May 08, 2010 12:08 pm
anjaligeorge1 wrote:A certain circle in the xy-plane has radius of 2 and has its center at the origin. If line L is tangent with the circle, what is the slope of the circle?
(1) L passes through point (0, 2).
(2) L passes through point (3, 2).
slope of the cirlce??????

i'll assume you meant slope of L.

st1:

since this point lies on the circle, the tangent in this case will be || to the X axis. hence, sufficient.

St2:

there can be two tangents, as the point lies outside the circle. Hence, insufficient.

IMO A
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Harsha
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by gmatmachoman » Sat May 08, 2010 12:16 pm
Harsha,

small doubt in the question there...Is it asking the slope of the tangent line or indeed the slope of circle??

i never know we culd find one for circle!!
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by harshavardhanc » Sat May 08, 2010 12:22 pm
gmatmachoman wrote:Harsha,

small doubt in the question there...Is it asking the slope of the tangent line or indeed the slope of circle??

i never know we culd find one for circle!!
i too think it's the slope of L that we've to find out.
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by moliver » Sat May 08, 2010 1:56 pm
circle can have a slope? I don't think so.
I was wrong, the answer seems to be A
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