Taylor Series is based on a theorem that states, any smooth function, 𝑓(𝑥), can be expressed as a polynomial in the neighborhood of a point 𝑎. Assuming all derivatives of the function exist at 𝑎, the series takes the form
f(a) = C0
The derivative of f(x) by differentiating the individual terms,
the derivative is also a power series, then computing all of its higher derivatives
when the function is evaluated at a, the constant term is obtained for each power series.
f'(a) = 1 · C1
f''(a) = 2 · 1 · C2
f'''(a) = 3 · 2 · 1 · C3
.. . . .
f(k)(a) = k! · Ck
Solving the equation for the k-th coefficient Ck,
If function has a power series expansion at a with radius of convergence R > 0, that is,
then Cn,
Substituting Cn value in the formula,
When a = 0, the series becomes
which is called Maclaurin series.