derivative.py

def approximate_derivative(self, x):
    """
        Estimates the derivative of a function f(x) from its Taylor series.

        Useless since we need the derivative of the actual function to find the series
    """
    value = 0
    for i in range(1, len(self.coefficients)): # skip the first value (constant) as the derivative is 0
        value += self.coefficients[i] * i * ((x - self.center)**(i-1)) # differentiate each term: x^n => n*x^(n-1)
    return value