SOLUTION: Show that the line containing the points (a, b)and (b, a), where a does not equal b ,is perpendicular to the line y = x. Also, show that the midpoint of (a,b)and (b,a) lies on the

Algebra ->  Equations -> SOLUTION: Show that the line containing the points (a, b)and (b, a), where a does not equal b ,is perpendicular to the line y = x. Also, show that the midpoint of (a,b)and (b,a) lies on the       Log On


   



Question 1207884: Show that the line containing the points (a, b)and (b, a), where a does not equal b ,is perpendicular to the line y = x. Also, show that the midpoint of (a,b)and (b,a) lies on the line y = x .
Answer by ikleyn(52781) About Me  (Show Source):
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(a) Show that the line containing the points (a, b)and (b, a), where a does not equal b, is perpendicular to the line y = x.
(b) Also, show that the midpoint of (a,b)and (b,a) lies on the line y = x .
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(a)  The line, containing points  (a,b)  and  (b,a),  has the slope


         m%5B1%5D = %28a-b%29%2F%28b-a%29 = -1.


     The line  y = x  has the slope  m%5B2%5D = 1.


     Since  m%5B1%5D%2Am%5B2%5D = 1*(-1) = -1,  the numbers m%5B1%5D and m%5B2%5D are opposite reciprocal.


     From this, we conclude that these two lines are perpendicular.



(b)  The midpoint is  (%28a%2Bb%29%2F2,%28b%2Ba%29%2F2).

     Thus you see that x-coordinate of the midpoint is equal to its y-coordinate.


      From this, we conclude that the midpoint lies on the line y = x.

At this point, the solution is complete, with all necessary explanations.