Difference between revisions of "2011 AIME I Problems/Problem 3"
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Thus, we have that <math>\alpha=-\frac{123}{13}</math> and that <math>\beta=\frac{526}{13}</math>. It follows that <math>\alpha+\beta=-\frac{123}{13}+\frac{526}{13}=\frac{403}{13}=\boxed{031}</math>. | Thus, we have that <math>\alpha=-\frac{123}{13}</math> and that <math>\beta=\frac{526}{13}</math>. It follows that <math>\alpha+\beta=-\frac{123}{13}+\frac{526}{13}=\frac{403}{13}=\boxed{031}</math>. | ||
== Note == | == Note == | ||
− | Since AIME only accepts nonnegative integer solutions up to 999, once we find the distances, since the sum of the absolute values of the abscissa and ordinate is not divisible by <math>13</math> and therefore cannot be a valid solution, the answer must be the difference instead. | + | Since AIME only accepts nonnegative integer solutions up to <math>999</math>, once we find the distances, since the sum of the absolute values of the abscissa and ordinate is not divisible by <math>13</math> and therefore cannot be a valid solution, the answer must be the difference instead. |
==Video Solution== | ==Video Solution== |
Revision as of 23:57, 11 July 2022
Contents
[hide]Problem
Let be the line with slope
that contains the point
, and let
be the line perpendicular to line
that contains the point
. The original coordinate axes are erased, and line
is made the
-axis and line
the
-axis. In the new coordinate system, point
is on the positive
-axis, and point
is on the positive
-axis. The point
with coordinates
in the original system has coordinates
in the new coordinate system. Find
.
Solution
Given that has slope
and contains the point
, we may write the point-slope equation for
as
.
Since
is perpendicular to
and contains the point
, we have that the slope of
is
, and consequently that the point-slope equation for
is
.
Converting both equations to the form , we have that
has the equation
and that
has the equation
.
Applying the point-to-line distance formula,
, to point
and lines
and
, we find that the distance from
to
and
are
and
, respectively.
Since and
lie on the positive axes of the shifted coordinate plane, we may show by graphing the given system that point P will lie in the second quadrant in the new coordinate system. Therefore, the abscissa of
is negative, and is therefore
; similarly, the ordinate of
is positive and is therefore
.
Thus, we have that and that
. It follows that
.
Note
Since AIME only accepts nonnegative integer solutions up to , once we find the distances, since the sum of the absolute values of the abscissa and ordinate is not divisible by
and therefore cannot be a valid solution, the answer must be the difference instead.
Video Solution
https://www.youtube.com/watch?v=_znugFEst6E&t=919s
~Shreyas S
See also
2011 AIME I (Problems • Answer Key • Resources) | ||
Preceded by Problem 2 |
Followed by Problem 4 | |
1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 • 9 • 10 • 11 • 12 • 13 • 14 • 15 | ||
All AIME Problems and Solutions |
The problems on this page are copyrighted by the Mathematical Association of America's American Mathematics Competitions.