If `x y=c^2` , find `(dy)/(dx)`

Explanation

$$ x y=c^{2}......(1) $$
Differentiating both sides w.r.t `x`
$$
\begin{aligned}
& x \times \frac{d y}{d x}+1 \times y=0 \\
\Rightarrow \quad & x \frac{d y}{d x}+y=0 \\
...