Is there any benefit to using Taylor series centered at nonzero value

In summary, we discussed the use of Maclaurin series to approximate function values and the importance of choosing an appropriate expansion point. We also noted that while a Taylor series can be written around any point, it may not accurately represent the function at points other than the center. Additionally, we saw an example of using a Taylor series to find approximations for angles and its application in solving differential equations.
  • #1
Turion
145
2
over a Maclaurin series?

Also, how do I calculate e^0 using Maclaurin series? I'm getting 0^0.
 
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  • #2
Try to express ln(x) as series around x=0 ;)
Of course, instead of using 1 as expansion point, you can expand ln(x-1) around x=0, but that just gives the same result.

If you want to approximate the function value somewhere, it can be useful to consider an expansion point close to that.

0^0 has to be defined as 1 here to get a correct series, but you need the value of e^0 anyway to calculate the series of e^x around x=0.
 
  • #3
mfb said:
If you want to approximate the function value somewhere, it can be useful to consider an expansion point close to that.

Why? Can't you use any Taylor series centered at any point?

Also, when I calculate e^2 using Taylor series centered at 2, I get 0 since x-a=2-2=0. I just noticed that in order to calculate any power of e, you need to know that power of e first. Doesn't that make it kind of pointless?
 
  • #4
Turion said:
Why? Can't you use any Taylor series centered at any point?
No - the function that is represented by the Taylor series has to be defined and infinitely differentiable at that point. So you can't write a Taylor series centered around a = 0 for ln(x).
Turion said:
Also, when I calculate e^2 using Taylor series centered at 2, I get 0 since x-a=2-2=0.
I just noticed that in order to calculate any power of e, you need to know that power of e first. Doesn't that make it kind of pointless?
The idea is that if you know the exact value of your function at some point a, you can use a Taylor series to find approximations at points near a. For example, we know that cos(60°) = cos(##\pi/3##) = .5, exactly. We can use a Taylor series expansion about a = ##\pi/3## to get reasonable approximations to angles such as 60.5°, and so on.
 
  • #5
Mark44 said:
No - the function that is represented by the Taylor series has to be defined and infinitely differentiable at that point. So you can't write a Taylor series centered around a = 0 for ln(x).
I would like to point out that the function [itex]f(x)= e^{-1/x^2}[/itex] if [itex]x\ne 0[/itex], f(0)= 0, is infinitely differentiable so you can write a Taylor series centered around x= 0, just as Mark44 says but that Taylor series is not equal to f(x) anywhere except at x= 0.

The idea is that if you know the exact value of your function at some point a, you can use a Taylor series to find approximations at points near a. For example, we know that cos(60°) = cos(##\pi/3##) = .5, exactly. We can use a Taylor series expansion about a = ##\pi/3## to get reasonable approximations to angles such as 60.5°, and so on.

Another reason to use a Taylor series around a value other than 0 is to find a series solution to a linear differential equation with "initial values" given at some non-zero point.
 
  • #6
Turion said:
over a Maclaurin series?

Also, how do I calculate e^0 using Maclaurin series? I'm getting 0^0.

ex = 1 + x + x2/2! + ...
therefore e0 = 1.
 

FAQ: Is there any benefit to using Taylor series centered at nonzero value

What is a Taylor series and how is it used?

A Taylor series is a mathematical representation of a function as an infinite sum of terms. It is used to approximate a function at a specific point by using information about the function's derivatives at that point.

What does it mean for a Taylor series to be centered at a nonzero value?

A Taylor series is centered at a nonzero value when the point of approximation is not at zero, but at a different value on the function's domain. This means that the series will be a representation of the function at that specific point.

Are there any benefits to using Taylor series centered at nonzero values?

Yes, there are benefits to using Taylor series centered at nonzero values. This allows for a more accurate approximation of a function at a specific point, especially when the function is not symmetric around the origin.

Can a Taylor series centered at a nonzero value be used for any function?

In theory, a Taylor series can be used for any function. However, the series may only converge for certain functions and may require an infinite number of terms to accurately represent the function.

How can I determine the accuracy of a Taylor series centered at a nonzero value?

The accuracy of a Taylor series centered at a nonzero value can be determined by comparing the series to the actual function at the point of approximation. The more terms that are used in the series, the more accurate the approximation will be.

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