// Numbas version: finer_feedback_settings {"name": "Simple irreducible quadratic factor partial fractions", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"functions": {}, "preamble": {"css": "", "js": ""}, "statement": "

Determine the partial fraction breakdown of the following expression:

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     \\(I(s)=\\frac{\\var{R}s^2+\\var{T}}{(s+\\var{a})(s^2+\\simplify{{b}^2})}\\)

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\\(\\frac{\\var{R}s^2+\\var{T}}{(s+\\var{a})(s^2+\\simplify{{b}^2})}=\\frac{A}{s+\\var{a}}+\\frac{Bs+C}{(s^2+\\simplify{{b}^2})}\\)

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Mutiply across by the denominator \\((s+\\var{a})(s^2+\\simplify{{b}^2})\\) to get

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\\(\\var{R}s^2+\\var{T}=A(s^2+\\simplify{{b}^2})+Bs(s+\\var{a})+C(s+\\var{a})\\)

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let s = \\(-\\var{a}\\)

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\\(\\simplify{{R}*{a}^2+{T}}=\\simplify{({a}^2+{b}^2)}A\\)

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\\(A=\\simplify{({R}*{a}^2+{T})/({a}^2+{b}^2)}\\)

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let s = \\(0\\)

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\\(\\var{T}=\\simplify{{b}^2}A+\\var{a}C\\)

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\\(\\var{T}-\\simplify{{b}^2}*\\simplify{{({R}*{a}^2+{T})/({a}^2+{b}^2)}=\\var{a}C\\)

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\\(C=\\simplify{({a}*{T}-{a}*{R}*{b}^2)/({a^2}+{b}^2)}\\)

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coefficient of \\(s^2 = \\var{R}\\)

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\\(\\var{R}=A+B\\)

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\\(B=\\var{R}-A\\)

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\\(B=\\simplify{({R}*{b}^2-{T})/({a}^2+{b}^2)}\\)

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Manipulation of algebraic fractions

", "licence": "Creative Commons Attribution 4.0 International"}, "parts": [{"variableReplacements": [], "gaps": [{"checkingaccuracy": 0.001, "checkvariablenames": false, "marks": "3", "showFeedbackIcon": true, "expectedvariablenames": [], "answer": "(({T}+{a}^2*{R})/(({b}^2+{a}^2)))/(s+{a})+(((-{T}+{b}^2*{R})/(({b}^2+{a}^2)))s)/(s^2+{b}^2)+(({a}*{T}-{b}^2*{a}*{R})/({a}^2+{b}^2))/(s^2+{b}^2)", "showpreview": true, "scripts": {}, "vsetrangepoints": 5, "variableReplacements": [], "showCorrectAnswer": true, "checkingtype": "absdiff", "vsetrange": [0, 1], "variableReplacementStrategy": "originalfirst", "type": "jme"}], "showCorrectAnswer": true, "showFeedbackIcon": true, "prompt": "

Express your answer as a sum fractions:

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               \\(I(s) =\\) [[0]]

", "type": "gapfill", "variableReplacementStrategy": "originalfirst", "marks": 0, "scripts": {}}], "type": "question", "contributors": [{"name": "Frank Doheny", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/789/"}]}]}], "contributors": [{"name": "Frank Doheny", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/789/"}]}