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circle-line intersection

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by mkhanna » Thu Sep 24, 2009 8:32 am
Circle C and line K lie in the xy-plane. If circle C is centered at the origin and has radius 1, does line K intersect circle C?
1) The x-intercept of line K is greater than 1.
2) The slope of line K is -1/10.
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Source: — Data Sufficiency |

by sreak1089 » Thu Sep 24, 2009 9:10 am
Is it E?
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Re: circle-line intersection

by maihuna » Thu Sep 24, 2009 9:21 am
mkhanna wrote:Circle C and line K lie in the xy-plane. If circle C is centered at the origin and has radius 1, does line K intersect circle C?
1) The x-intercept of line K is greater than 1.
2) The slope of line K is -1/10.
This question actually asks whether we can determine the line equation from given info, if we can not determine the line info we can not make whether it will pass through some point 1 x

from 1 for y=0, x>1 so : 0 = mx+c => c = -mx >-m

from 2> m = -1/10 so y = -1/10x + c

combine the two: y = -1/10x + c
we can only get info about c

so we can not uniquely define K.

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