`A B` is a variable line sliding between the coordinate axes in such a way that `A` lies on the x-axis and `B` lies on the y-axis. If `P` is a variable point on `A B` such that `P A=b ,P b=a` , and `A B=a+b ,` find the equation of the locus of `Pdot`

Answer

`(x^(2))/(a^(2))+(y^(2))/(b^(2))=1`