SOLUTION: Obtain the equation of a straight line that is symmetric to line l: y=x-3 with respect to line m: (-1/3)x-(1/3).

Algebra ->  Graphs -> SOLUTION: Obtain the equation of a straight line that is symmetric to line l: y=x-3 with respect to line m: (-1/3)x-(1/3).      Log On


   



Question 1062846: Obtain the equation of a straight line that is symmetric to line l: y=x-3 with respect to line m: (-1/3)x-(1/3).
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
First find the point of intersection,
x-3=-x%2F3-1%2F3
x%2Bx%2F3=3-1%2F3
%284%2F3%29x=8%2F3
x=2
So then,
y=2-3
y=-1
Now find the perpendicular bisector of the line, y=-x%2F3-1%2F3},
you know that the slope of the bisector is equal to m=3 since perpendicular lines have slopes that are negative reciprocals.
So the line has the form y=3x%2Bb
Choose a point on the line.
I'll choose (5,-2).
So the equation of the perpendicular bisector using point slope form would be,
y%2B2=3%28x-5%29
y=3x-15-2
y=3x-17
The intersection point of the perpendicular bisector with the original line can be found,
x-3=3x-17
-2x=-14
x=7
and
y=7-3
y=4
(7,4)
So then using (5,-2) as the center point and (7,4) as the intersection point, find the corresponding intersection point with the symmetric line.
To go from the center point to the intersection point, you move 2 units in x and 6 units in y. The intersection point of the symmetric line will have the same value but just different sign.
So starting at (5,-2) you would move -2 in the x and -6 in the y.
(5,-2)+(-2,-6)=((3,-8)
So now you know the symmetric line goes through (3,-8) and (2,-1).
Find the slope,
m=%28-8-%28-1%29%29%2F%283-2%29=-7
Then use the point slope form,
y-%28-8%29=-7%28x-3%29
y%2B8=7x%2B21
highlight%28y=13-7x%29
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