Find $\frac{\text{d}\text{e}\text{l}\text{w}}{\text{d}\text{e}\text{l}\text{s}}$ and $\frac{\text{d}\text{e}\text{l}\text{w}}{\text{d}\text{e}\text{l}\text{t}}$ for $w=2xy,$ where $x=s^2+t^2$ and $y=\frac{s}{t}by$ substituting $in$ for

$x$ and $y,$ and then finding the partial derivatives directly.