1 - Enter and edit function $f(x,y)$ in two variables, x and y, and click "Enter Function".
The five operators used are: + (plus) , - (minus), / (division) , ^ (power) and * (multiplication). (example: f(x,y) = x/y - 2*x + 2*x*y).(more notes on editing functions are located below)
2 - Click "Calculate Derivative" to obain $\dfrac{\partial f}{ \partial x}$ and $\dfrac{\partial f}{ \partial y}$ in two steps each. The first step using the rules of derivatives and the second is the simplified form of the derivative.

Notes: In editing functions, use the following:
1 - The five operators used are: + (plus) , - (minus), / (division) , ^ (power) and * (multiplication). (example: f(x,y) = x/y - 2*x + 2*x*y)
2 - The function square root function is written as (sqrt). (example: sqrt(x^2-1)
3 - The exponential function is written as (exp). (Example: exp(x+2) )
4 - The ln function is written as (log). (Example: log(2x+3) )
5 - The absolute value function is not supported directly but you can transform an absolute value function into a square root function as follows: | u | = sqrt(u^2)