|
Question 152310: 26.) The midpoint of the line segment joining a moving point to (6,0) is on the line y=x. Find the equation of its locus.
Ans. x-y+6=0
This is a question that comes with the answer but I don't know how to solve for it. I tried using the midpoint formula but the answer is either x+y-6=0 or x-y-6=0. I don't know how to solve for this kind of problem...
Answer by Edwin McCravy(20054) (Show Source):
You can put this solution on YOUR website! 26.) The midpoint of the line segment joining a moving point to (6,0) is on the line y=x. Find the equation of its locus.
Ans. x-y+6=0
Graph the line :
Call point (6,0) the point R.
Draw an arbitrary line from point R(6,0), crossing the
line at point M, and extending to P so that MP
equals RM. making M the midpoint of RP. P is the moving
point.
Label the moving point P with the variable coordinates (x,y)
Since point M is the midpoint of the line segment RP, we use
the midpoint formula to label M with the coordinates
( , ) or ( , )
Now the point M( , ) is on the line , so
it must satisfy the equation , so we substitute that point
into the equation and we get:
Multiply both sides by 2:
That is equivalent to
To see the path of the moving point we draw the graph of
in green
Edwin
|
|
|
| |