Taylor Series Tips: Learn & Understand Power Series

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Discussion Overview

The discussion revolves around understanding Taylor series and their relationship to power series. Participants seek clarification on definitions, differences, and methods of proving that a function can be represented by a Taylor series. The conversation includes both conceptual and technical aspects of the topic.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant expresses difficulty in understanding Taylor series and seeks tips on differentiating it from power series, its purpose, and methods of proof.
  • Another participant asserts that a Taylor series is a specific type of power series and explains that if a power series equals a function, it must be the Taylor series for that function.
  • A participant provides an example of calculating the Taylor series for the function f(x) = 1/(1-x) at x=0, illustrating two methods of deriving the series.
  • There is a mention of Maclaurin series as a special case of Taylor series, which involves powers of (x-a) where "a" is an arbitrary constant.
  • A question is raised regarding the nature of "a" as arbitrary and its role as the "center" of the series.
  • Another participant confirms that "a" refers to the center of the interval of convergence.

Areas of Agreement / Disagreement

Participants generally agree on the relationship between Taylor series and power series, but there are questions regarding the definitions and implications of the center "a" in Taylor series. The discussion remains unresolved on some conceptual points.

Contextual Notes

Some assumptions about the definitions of Taylor and power series may not be fully articulated, and the discussion does not resolve the nuances of convergence or the implications of the center "a".

toni
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I really need some tips on taylor series...Im trying to learn it myself but i couldn't understand what's on the book...

Can anyone who has learned this give me some tips...like what's the difference between it and power series (i know it's one kind of power series), why people develop it, and is there any standard way to prove that a function can be represent by a particular taylor series?

Thank you soooo much!
 
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A Taylor series is just a power series calculated in a particular way. Not only is it true that a Taylor series is a type of power series, but if a power series is equal to a function, it must be the Taylor series for that function.

That means I can calculate the Taylor series for, say, f(x)= 1/(1-x), at x= 0, in two different ways:
Using the definition, find the derivatives, evaluate at x= 0, and put those into the formlula: f(0)= 1, f'(x)= (1- x)=2 so f'(0)= 1, f"= 2(1-x)-3 so f"(0)= 2, ..., f(n)(x)= n!(1-x)n so fn[/sub](0)= n! and therefore,
\sum \frac{f^{(n)}(0)}{n!}x^n= \sum x^n

Or just recall that the sum of a geometric series, \sum ar^n is 1/(1- r). Since 1/(1-x) this must be a geometric series with a= 1 and r= x: That gives
\frac{1}{1-x}= \sum x^n
just as before. Because they are power series converging to the same function, they musst be exactly the same.
 
The description given by Halls of Ivy is a special case of Taylor, call MacLauren (sp?) series. In general Taylor series involve powers of (x-a) where a is an arbitrary constant.
 
is "a" arbitrary? "a" is also said to be the "center" right?
 
If you mean the center of the interval of convergence, yes.
 

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