Taylor expansions and integration.

In summary, it is possible to use a Taylor series expansion to approximate the value of a definite integral for a function that cannot be integrated analytically, as long as the function is analytic around the point and the interval between the integral limits is short. This method may not be exact, but it can provide a good approximation.
  • #1
JamesHG
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I have a short doubt: Let f(x) be a fuction that can't be integrated in an analytical way . Is anything wrong if I expand it in a Taylor' series around a point and use this expansion to get the value of the definite integral of the function around that point? Suppose that the interval between the integral limits it's short so that the expansion is a good approximation to the function in that interval.
Thanks!
 
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  • #2
JamesHG said:
I have a short doubt: Let f(x) be a fuction that can't be integrated in an analytical way . Is anything wrong if I expand it in a Taylor' series around a point and use this expansion to get the value of the definite integral of the function around that point? Suppose that the interval between the integral limits it's short so that the expansion is a good approximation to the function in that interval.
Thanks!

If the function is analytic around the point (i.e. all the derivatives exist and or finite at the point), I cannot see any problem. Obviously, unless you use infinite number terms it will usually only be an approximation to your integral over f(x).
 

1. What is a Taylor expansion?

A Taylor expansion is a mathematical tool used to approximate a function using a polynomial. It is based on the idea that any smooth function can be approximated by a sum of infinitely many polynomials of increasing degree.

2. Why are Taylor expansions important in integration?

Taylor expansions are important in integration because they allow us to evaluate complicated integrals by breaking them down into simpler integrals that can be solved using basic integration rules. This makes integration more efficient and accurate.

3. How do you find the Taylor series for a function?

The Taylor series for a function can be found by repeatedly taking derivatives of the function at a specific point and evaluating them at that point. The coefficients of the resulting terms form the Taylor series.

4. What is the relationship between Taylor series and integration?

The relationship between Taylor series and integration is that Taylor series can be used to approximate the value of an integral. By finding the Taylor series of a function, we can substitute it into an integral and evaluate the integral term by term, which gives us an approximation of the integral.

5. How accurate are Taylor series approximations?

The accuracy of a Taylor series approximation depends on the number of terms used in the series. The more terms included, the more accurate the approximation will be. However, in some cases, the Taylor series may not converge to the actual value of the function, so care must be taken when using these approximations.

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