Question Number 90299 by zainal tanjung last updated on 22/Apr/20
$$\mathrm{help}\:\mathrm{me} \\ $$$$ \\ $$$$\mathrm{z}\left(\mathrm{x},\mathrm{y}\right)=\mathrm{xy}.\mathrm{ln}\:\mathrm{xy} \\ $$$$\mathrm{z}_{\mathrm{x}} ^{'} =…?\:\:\:\mathrm{and}\:\:\mathrm{z}'_{\mathrm{y}} =…? \\ $$