It is required from you to write a Python code that:
- asks the user to enter the coordinates x and y of a point in R²
- calculates the gradient of the function f(x,y) = x³y - xy³ at this point
- handles the case where the user writes non numerical values
- asks the user the components of the vector u
- creates a unit vector u' out of u
- computes the directional derivative of f at the point given by the user in the direction of the vector u (also given by the user)
The way to display the gradient at this point as well as the directional derivative is up to you.