Question

Determine the locus of a point P which moves so that the difference of the squares of its distances from two fixed P'(4,0) and P(-4,0) is constant

Answer 1

is it a st line

Answer 2

let the moving pt be x,y
then by the prob (x+4)^2+y^2- (x-4)^2 -y^2 =k (constant say)
or 16x=k or x=k/16 (line parallel to y axis)