Center matters
The polynomial matches the function and its first n derivatives at the center. It is generally most useful near that center.
Construct a Taylor polynomial about any center or a Maclaurin polynomial about zero. See each derivative, factorial and coefficient, compare the approximation at a point, and graph it against the original function—all locally in your browser.
For each degree k, calculate f⁽ᵏ⁾(a), divide by k!, then multiply by (x−a)ᵏ.
Calculate a polynomial to see every coefficient step.
Calculate a polynomial to compare it with the original function near the expansion center.
exp(x), sin(x), ln(x), or 1/(1+x^2).f(a) through f⁽ⁿ⁾(a).A Maclaurin polynomial uses the same formula with a=0. The calculator constructs the finite polynomial Pn; it does not claim that the corresponding infinite series converges to the function at every point.
The polynomial matches the function and its first n derivatives at the center. It is generally most useful near that center.
A higher order adds derivative information, but it does not guarantee lower error at every point or outside the interval of convergence.
The function and every required derivative must be real and finite at the center. For example, ln(x) cannot be expanded about 0 over the reals.
At the optional point, signed error is f(x)−Pₙ(x). This observed difference is not a symbolic remainder bound.
Every derivative of e^x equals e^x, so every derivative at 0 is 1.
P₄(x)=1+x+x²/2+x³/6+x⁴/24.
Derivative values at 0 repeat 0, 1, 0, −1.
P₇(x)=x−x³/6+x⁵/120−x⁷/5040.
Let h=x−1. The signs alternate after the linear term.
P₄(x)=h−h²/2+h³/3−h⁴/4.
A Taylor expansion uses a general center a. A Maclaurin expansion is precisely the Taylor expansion centered at zero.
It propagates a truncated power series through the parsed expression using Taylor-mode automatic differentiation. The degree-k coefficient is mathematically the same as f⁽ᵏ⁾(a)/k!; the table shows that derivative value, factorial and coefficient.
The calculator stops at the selected finite order. An infinite Taylor series also requires a convergence analysis before it can be identified with the original function away from the center.
No. It commonly improves local accuracy for analytic functions inside their convergence interval, but the outcome depends on the function, center and evaluation point.
The function or one of the required derivatives is undefined, non-real or infinite there. Examples include ln(x) at 0, 1/x at 0 and abs(x) at its corner.
Radians. Standard calculus derivative and Taylor-series formulas for trigonometric functions assume radian measure.
No. All parsing, symbolic differentiation, evaluation, graphing and export happen locally on your device.