Pure Partial Derivative

Definition

• With $f:{\mathbb{R}}^2\to \mathbb{R}$ being Differentiable
• With partial derivatives $\frac{\partial f}{\partial x},\frac{\partial f}{\partial x}$
• The pure partial derivatives include: $\frac{{\partial }^{2}f}{\partial x^2},\frac{{\partial }^{2}f}{\partial y^2}$