// Numbas version: exam_results_page_options {"name": "Maclaurin series (first three terms)", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"metadata": {"licence": "Creative Commons Attribution 4.0 International", "description": "

Find the first 3 terms in the MacLaurin series for $f(x)=(a+bx)^{1/n}$ i.e. up to and including terms in $x^2$.

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The general formula for the Maclaurin Series for a function $f(x)$ is

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$f(x) = f(0) + f'(0)x + \\frac{f''(0)}{2!}x^2 + \\dots + \\frac{f^{n}(0)}{n!}x^n + \\dots$

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For this example,
\\[\\begin{eqnarray*} f'(x)&=&\\simplify[all,fractionNumbers]{{b}/{n}*({a}+{b}x)^(-{n-1}/{n})}\\\\[10pt] f''(x)&=&\\simplify[all,fractionNumbers]{-{b^2*(n-1)}/{n^2}*({a}+{b}x)^(-{2*n-1}/{n})} \\end{eqnarray*} \\]
and so we get:
\\[\\begin{eqnarray*} f(0)&=\\simplify[all]{{a}^(1/{n})={tm0}}\\\\[10pt] f'(0)&=\\simplify[all,fractionNumbers]{{tm1}/{a*n}}\\\\[10pt] f''(0)&=\\simplify[all,fractionNumbers]{{tm2}/{a^2*n^2}} \\end{eqnarray*}\\]
Hence the first three terms of the Maclaurin series are:
\\[\\simplify[all,fractionNumbers,!collectNumbers]{{tm0}+{tm1}/{a*n}*x+{tm2}/{2*a^2*n^2}*x^2} \\]

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For further information see Chapter 2 - Series notes.

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Consider the function $f(x)=(\\simplify[all]{{a}+{b}*x})^{1/\\var{n}}$.

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Find the first 3 terms in the Maclaurin series for $f(x)$, i.e. up to terms in $x^2$.

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Input coefficients as fractions, not as decimals. Also do not use factorials in your answer. For example, input 6 rather than 3!.

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