Question

What is the difference between 'x' being proportional to 'y' and 'y' being proportional to 'x'??

Answer 1

(X-y)(x+y)/xy

Answer 2

The proportionality constants will be inverses:

\[x\propto y\implies x=\alpha y\\[2ex]
y\propto x\implies y=\beta x\\[2ex]
\therefore\quad \alpha =\frac 1\beta \]