Find the locus of a point equidistant from two lines y=sqrt3xy=3x and y=1/sqrt3xy=13x?

1 Answer
Nov 3, 2017

Locus is given by pair of lines given by x^2-y^2=0x2y2=0 i.e. x+y=0x+y=0 and x-y=0xy=0

Explanation:

All points on lines bisecting are equidistant from the two given lines.

Let the equation of lines be y=m_1x+c_1y=m1x+c1 and y=m_2x+c_2y=m2x+c2

or m_1x-y+c_1=0m1xy+c1=0 and m_2x-y+c_2=0m2xy+c2=0

The distance of point (x,y)(x,y) from m_1x-y+c_1=0m1xy+c1=0 is

|(m_1x-y+c_1)/sqrt(1+m_1^2)|∣ ∣ ∣m1xy+c11+m21∣ ∣ ∣

and the distance of point (x,y)(x,y) from m_2x-y+c_2=0m2xy+c2=0 is

|(m_2x-y+c_2)/sqrt(1+m_2^2)|∣ ∣ ∣m2xy+c21+m22∣ ∣ ∣

and equation of angular bisectors would be

(m_1x-y+c_1)/sqrt(1+m_1^2)=+-[(m_2x-y+c_2)/sqrt(1+m_2^2)]m1xy+c11+m21=±⎢ ⎢m2xy+c21+m22⎥ ⎥

For example , if two lines are y=sqrt3xy=3x and y=1/sqrt3xy=13x,

then equations would be

(sqrt3x-y)/sqrt(1+3)=+-[(1/sqrt3x-y)/sqrt(1+1/3)]3xy1+3=±⎢ ⎢13xy1+13⎥ ⎥

or (sqrt3x-y)/2=+-[(x-sqrt3y)/2]3xy2=±[x3y2]

i.e. (sqrt3-1)/2x+(sqrt3-1)/2y=0312x+312y=0 and (sqrt3+1)/2x-(sqrt3-1)/2y=03+12x312y=0

or (sqrt3-1)x+(sqrt3-1)y=0(31)x+(31)y=0 and (sqrt3+1)x-(sqrt3+1)y=0(3+1)x(3+1)y=0

or x+y=0x+y=0 and x-y=0xy=0 or (x+y)(x-y)=0(x+y)(xy)=0 i.e. x^2-y^2=0x2y2=0

graph{(x+y)(x-y)(sqrt3x-y)(x-sqrt3y)=0 [-10, 10, -5, 5]}