How Do You Calculate Error Bounds for Maclaurin Polynomial Approximations?

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Discussion Overview

The discussion revolves around calculating error bounds for Maclaurin polynomial approximations, specifically in the context of integrating the function e^(x^2) from x=0 to x=0.5. Participants explore the formulation of the polynomial, error estimation, and integration techniques.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant presents a 5th degree polynomial approximation for e^(x^2) as 1 + x^2 + (1/2)(x^4) and queries how to find the upper bound on the error.
  • Another participant suggests that the polynomial should include additional terms and questions the correctness of the initial polynomial provided.
  • There is a reference to the Maclaurin series expansion and the process of substituting t with x^2 to derive the series.
  • One participant expresses uncertainty about how to proceed with finding the upper bound on the error and approximating the integral.
  • Another participant emphasizes the need to integrate the polynomial to find the approximation of the integral.

Areas of Agreement / Disagreement

Participants express differing views on the correct formulation of the Maclaurin polynomial, with some asserting the need for more terms while others defend their initial calculations. The discussion remains unresolved regarding the exact polynomial and the method for calculating the error bounds.

Contextual Notes

Participants reference the Taylor series and Maclaurin series, but there are indications of missing assumptions regarding the degree of accuracy required for the polynomial approximation and the specific error estimation techniques to be used.

chief10
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Now I'm trying to get my head around this question. I just know they're going to give us a large degree question like this in the exam...

Let's say:

I = ∫[e^(x^2)]dx with nodes being x=0 to x=0.5

The 5th degree polynomial is 1 + x^2 + (1/2)(x^4)

So my queries are:

How would I go about finding the upper bound on the error from 0 to 0.5? - My working gives 0.012
How do I get an approximation of I by integrating? - my working gives 0.545
How would I get an upper bound on the integration in the previous question?

Thanks a lot guys and girls.
 
Last edited:
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chief10 said:
Now I'm trying to get my head around this question. I just know they're going to give us a large degree question like this in the exam...

Let's say:

I = integral[e^(x^2)]dx with nodes being x=0 to x=0.5

I calculated that the 5th degree poly of integrand e^(x^2) is
1+ (x^2) + (1/2)(x^4) + (24/25)(x^5) ----- correct me if I'm wrong here but i think it's okay
This is incorrect. The first few terms of the Maclaurin series for et are 1 + t + t2/2! + t3/3! + t4/4! + ...

If you replace t by x2, what do you get?


chief10 said:
So my queries are:

How would I go about finding the upper bound on the error?
How do I get an approximation of I? I'm guessing I'm going to have to integrate right?

Thanks a lot guys and girls.
 
i was working under this assumption:

P(x) = f(a) + f'(a)(x-a) + [f''(a)(x-a)^2]/2! + ...etc..

where a=0 for Maclaurin

hmm
 
Mark44 said:
This is incorrect. The first few terms of the Maclaurin series for et are 1 + t + t2/2! + t3/3! + t4/4! + ...

If you replace t by x2, what do you get?

alright going by that I've computed which i double checked with the taylor series for a=01 + x^2 + (1/2)(x^4)any ideas on the rest?
 
Last edited:
chief10 said:
alright going by that I've computed which i double checked with the taylor series for a=0


1 + x^2 + (1/2)(x^4)


any ideas on the rest?
So integrate! You know how to integrate that, don't you?
 
HallsofIvy said:
So integrate! You know how to integrate that, don't you?

no need to snap at me.. lol.. of course i do - look at my markings next to the bolded questions

i just thought i could get some insight and to see if i was doing it correctly
 

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