Question

answer it.......plz...??????

Answer 1

I'm just going to give you a hint:
$y = \frac{x}{x + a}$
since we have to eliminate a in dy/dx so separate a in the equation by:
$\frac{x + a}{x} = \frac{1}{y}$
so
$a \: = \frac{x}{y} - x$
differentiate this w.r.t. x