user: I'm working on some calculus problems and need help estimating derivatives. Could you find the derivative of f(x) = 3x^2 + 2x - 1 at x = 4, calculate the derivative of g(x) = 5x^3 - 3x^2 + 2x + 1 at x = -2, determine the derivative of h(x) = 2x^4 - 3x^3 + 2x^2 - x + 1 at x = 0, and get the derivative of i(x) = x^5 - 2x^4 + 3x^3 - 2x^2 + x - 1 at x = 1?

Available functions:
name: estimate_derivative
description: Estimate the derivative of a function at a given point.
parameters: type: dict
properties: function: type: string
description: The function to calculate the derivative of.
x: type: integer
description: The point to calculate the derivative at.
required: function
x