English: That means once you check that condition, want to, you want to see whether you can get a function u(x, y) such that that makes derivative of that should be your differential equation that, we can find such a u, it is called, then it is, that means the converse part is done.
Telugu: If we can do అంటే మీరు ఆ $\frac{\partial M}{\partial y} = \frac{\partial N}{\partial x}$ షరతు ను పరిశీలన చేసిన తర్వాత, మీకు కావలసిన u(x, y) ఫంక్షన్‌ని పొందగలరో లేదో చూడాలి.