Changes

<math>\frac{\partial M}{\partial y} = \frac{\partial N}{\partial t}</math>

<math>\frac{\partial M}{\partial y} = \frac{\partial N}{\partial t}</math>

To find the solution of this equation, we assume that the solution is &phi; = constant. We assume that <math>\frac{\partial \phi}{\partial t} = M</math> and <math>\frac{\partial \phi}{\partial y} = N</math>. (If we substitute M and N back into (1), it yields <math>(\frac{\partial \phi}{\partial t}) dt + (\frac{\partial \phi}{\partial y}) dy = 0</math>, which makes sense.)

To find the solution of this equation, we assume that the solution is &phi; = constant. We assume the substitution <math>\frac{\partial \phi}{\partial t} = M</math> and <math>\frac{\partial \phi}{\partial y} = N</math>. (If we substitute M and N back into (1), it yields <math>(\frac{\partial \phi}{\partial t}) dt + (\frac{\partial \phi}{\partial y}) dy = 0</math>, which makes sense.)