# Taylor series with two variables

1. Feb 8, 2014

### JasonHathaway

Hi everyone,

1. The problem statement, all variables and given/known data + 2. Relevant equations + 3. The attempt at a solution

2. Feb 8, 2014

### ehild

It is correct so far.

ehild

3. Feb 8, 2014

### JasonHathaway

So the equations of d^2f and d^2f are correct? What are they called? (Total derivatives?)

4. Feb 8, 2014

### ehild

They are second-order and third-order total differentials. And you should write partial derivatives $\frac{\partial f}{\partial x}$, $\frac{\partial f}{\partial y}$ instead df/dx and df/dy, and so on... And the partial derivative $\frac{\partial^2 f}{\partial x\partial y}$ are not always the same as $\frac{\partial^2 f}{\partial y\partial x}$.

And you omitted dxdy from the second term of d^2 f

ehild

Last edited: Feb 8, 2014