Taylor formula is generally learned after learning derivative and differential, Rolle theorem, Lagrange mean value theorem and Cauchy mean value theorem.
Where f(x) is the function to be Taylor expanded; F(x0) is the function value at x = x0;
f'(x0),f''(x0),f ' '(x0),......,? F (n) (x0) is the derivative value of each order of the function at x = x0;
n! Represents the factorial of n. O ((x-x0) n) represents the ratio? (x-x0) n higher order infinitesimal.