An exact differential equation is formed by directly differentiating its primitive (solution) without any other process.

*Mdx + Ndy = 0*

is said to be an exact differential equation if it satisfies the following condition

∂M/∂y = ∂N/∂x

where ∂M/∂y denotes the differential coefficient of M with respect to y keeping x constant and ∂N/∂x is the differential coefficient of N with respect to x keeping y constant.

Method for solving Exact Differential Equations

- Integrate M w.r.t. x keeping y constant.
- Integrate w.r.t. y only those terms of N which do not contain x.
- Result of I + Result of II = Constant.