Hello, chaddy!

Find an equation of the set of points in the Cartesian plane

that are equidistant from the point and the lineCode:| | P | *(x,y) * / \ * A / | \ * * | \ * (-1,1) | * | * B | * - - - - * - - - - - - - - * | * |

The distance from point to point

. . is given by: .

The distance from a point to a line

. . is given by: .

Hence, the distance from to the line

. . is given by: .

Since , we have: .

Now simplify . . .