Taylor Series Problem - Question and my attempt so far

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jammyloller
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Question:

http://i.imgur.com/GsjeL.png

Here is my attempt so far:

http://i.imgur.com/AyOCm.png

Note: I've used m where the question has used j.

My attempt is based off some bad notes I took in class so the way I am trying to solve the problem may not be the best. I'm struggling to work out how to continue from the part where I've left a question mark, and I'm not even sure if the Taylor expansion is correct.

Could anybody offer some thoughts as to what to do?
 
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jammyloller said:
Question:

http://i.imgur.com/GsjeL.png

Here is my attempt so far:

http://i.imgur.com/AyOCm.png

Note: I've used m where the question has used j.

My attempt is based off some bad notes I took in class so the way I am trying to solve the problem may not be the best. I'm struggling to work out how to continue from the part where I've left a question mark, and I'm not even sure if the Taylor expansion is correct.

Could anybody offer some thoughts as to what to do?
Hello jammyloller. Welcome to PF !

Typeset problem 6.5: write the Taylor series for f(x0 + Δx) and f(x0 + 2Δx) up to (Δx)^3, then show Δ^j f(x0) / (Δx)^j ≈ f^(j)(x0) for j = 1 and j = 2 when |Δx| is small. Marked [15].


Handwritten notes on lined paper: a 'Note' heading, the identity sum from p=0 to m of (-1)^(m+p) f(x0 + qΔx) = Δ^m f(x0), a Taylor expansion of f(x0 + Δx) with terms f(x0'), 2Δx²/2!, 6Δx³/3!, and the step Δf(x0) = (-1)^(1+0)( ? ) with a question mark.


I'm not sure what your notes are supposed to say, but the Taylor expansion of f(x) about the point x0 is given by
[itex]\displaystyle f(x)=f(x_0)+f'(x_0)\Delta x<br /> +\frac{f''(x_0)}{2!}(\Delta x)^2+\frac{f'''(x_0)}{3!}(\Delta x)^3+\frac{f''''(x_0)}{4!}(\Delta x)^4+\dots\ ,\ \ \text{ where }\ \ \Delta x=x-x_0\ .[/itex]​
 
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  • Handwritten notes on lined paper: a summation from p=0 to m of (-1)^(m+p) f(x0 + qΔx) equals Δ^m f(x0), then a Taylor expansion of f(x0 + Δx) with terms f(x0'), f(x0''), and a partly written substitution Δf(x0) = (-1)^(1+0)( ? ).
    AyOCm.jpg
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  • Typeset problem 6.5 asking for the Taylor series of f(x0 + Δx) and f(x0 + 2Δx) to terms in (Δx)^3, then showing that Δ^j f(x0)/(Δx)^j ≈ f^(j)(x0) for j = 1 and j = 2 when |Δx| is small.
    GsjeL.png
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