Difference between revisions of "1977 AHSME Problems/Problem 5"

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== Problem 5 ==
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The set of all points <math>P</math> such that the sum of the (undirected) distances from <math>P</math> to two fixed points <math>A</math> and <math>B</math> equals the distance between <math>A</math> and <math>B</math> is
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<math>\textbf{(A) }\text{the line segment from }A\text{ to }B\qquad
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\textbf{(B) }\text{the line passing through }A\text{ and }B\qquad\\
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\textbf{(C) }\text{the perpendicular bisector of the line segment from }A\text{ to }B\qquad\\
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\textbf{(D) }\text{an ellipse having positive area}\qquad
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\textbf{(E) }\text{a parabola}    </math>
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==Solution==
 
==Solution==
 
Solution by e_power_pi_times_i
 
Solution by e_power_pi_times_i
  
 
The answer is <math>\textbf{(A)}</math> because <math>P</math> has to be on the line segment <math>AB</math> in order to satisfy <math>PA+PB=AB</math>.
 
The answer is <math>\textbf{(A)}</math> because <math>P</math> has to be on the line segment <math>AB</math> in order to satisfy <math>PA+PB=AB</math>.

Latest revision as of 12:27, 21 November 2016

Problem 5

The set of all points $P$ such that the sum of the (undirected) distances from $P$ to two fixed points $A$ and $B$ equals the distance between $A$ and $B$ is

$\textbf{(A) }\text{the line segment from }A\text{ to }B\qquad \textbf{(B) }\text{the line passing through }A\text{ and }B\qquad\\ \textbf{(C) }\text{the perpendicular bisector of the line segment from }A\text{ to }B\qquad\\ \textbf{(D) }\text{an ellipse having positive area}\qquad \textbf{(E) }\text{a parabola}$


Solution

Solution by e_power_pi_times_i

The answer is $\textbf{(A)}$ because $P$ has to be on the line segment $AB$ in order to satisfy $PA+PB=AB$.