Find series given values of derivatives

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Homework Help Overview

The discussion revolves around finding the power series expansion of a function \( f[x] \) given specific values of the function and its first two derivatives at \( x=0 \). The subject area pertains to series expansions and calculus.

Discussion Character

  • Exploratory, Conceptual clarification

Approaches and Questions Raised

  • Participants explore the formulation of the power series based on provided derivative values. There is an attempt to confirm the correctness of a proposed series expansion.

Discussion Status

Some participants express agreement with the proposed series expansion, while others encourage checking the values of the function and its derivatives to validate the solution. The discussion reflects a mix of confirmation and prompting for self-verification.

Contextual Notes

Participants note the absence of formal equations or methods for verification, relying instead on the provided derivative values and function evaluation at \( x=0 \).

boomer22
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Homework Statement


All you know about a function f[x] is:
f[0]=2, f '[0]=6, and f ''[0]=-8.
Write down the expansion of f[x] in powers of x through the x^2 term


Homework Equations


none


The Attempt at a Solution



I think the answer is 2 + 6x - 4x^2 , I just don't have any way to check so I want someone to confirm this.
 
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What you've written down certainly works.
 
morphism said:
What you've written down certainly works.

thanks a lot
 
boomer22 said:

Homework Statement


All you know about a function f[x] is:
f[0]=2, f '[0]=6, and f ''[0]=-8.
Write down the expansion of f[x] in powers of x through the x^2 term


Homework Equations


none


The Attempt at a Solution



I think the answer is 2 + 6x - 4x^2 , I just don't have any way to check so I want someone to confirm this.

You certainly can check it yourself! If f(x)= 2+ 6x- 4x2, what is f(0)? What is f'(0)? What is f''(0)?
 

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