% Approximates the derivative of the function f
% Make sure the file f.m is contained in the same folder as this file
% Input: x = value at which you want to find the derivative
% h = how close you want to the limit (h -> 0)
% Output: LLD = limit of the difference equation from the left side
% RLD = limit of the difference equation from the right side
function [LLD,RLD] = derivative(h,x)
% left limit
LLD = (f(x-h)-f(x))/(-h);
% right limit
RLD = (f(x+h)-f(x))/(h);