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Can anyone plot the degree-8 Maclaurin polynomial for the function $(x+1)/((x^2)-9)$ and function $(x+1)/((x^2)-9)$ on the same plot.

Please help, I've tried everything I could think of.

m_goldberg
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nik
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1 Answers1

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The problem is probably that Series returns a SeriesData object. It must be converted to a polynomial with Normal before it can be plotted.

f = (x + 1)/((x^2) - 9);
p = Normal[Series[f, {x, 0, 8}]]
Plot[{f, p}, {x, -2, 2}]

enter image description here

Henrik Schumacher
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    Plotting over a wider range will highlight the differences.

    Plot[{f, p}, {x, -4, 4}, PlotRange -> {-3, 3}, PlotLegends -> Placed[{"function", "polynomial"}, {.7, .7}]]

     – Bob Hanlon Apr 22 '19 at 03:04