We will use Python to calculate partial derivatives for the curve's equation. The library we will use is called `sympy`. First we need to import `sympy`: ```python from sympy import symbols, diff, simplify, init_printing init_printing() ``` Next, we need to define the curve's equation: ```python x, y, D, A = symbols('x y D A') k = A*x*y*(D**2) / (2*(D**2) + k*D**2) f = k*x*y + k*x*y * D / 2 display(f) ``` To get the partial derivative of this function with respect to `D` and with respect to `y`, we need to call a function that is provided by the `sympy` library called `diff`. Here we will tell `diff` to differentiate the function `f` with respect to `D`: ```python df_dD = diff(f, D) ``` Likewise, we will differentiate the function `f` with respect to `y`: ```python df_dy = diff(f, y) ``` We can then print the results of our differentiation: ```python print('df / dD') print(df_dD) print('df / dy') print(df_dy) ``` Next, we will discuss a method called Newton's method to solve for `y`: ```python y_n = y - f / df_dy ``` This is the end of this introductory lesson on partial derivatives.