// Numbas version: finer_feedback_settings {"name": "Luis's copy of Quotient rule - differentiate quadratic over quadratic", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"advice": "\n \n \n

The quotient rule says that if $u$ and $v$ are functions of $x$ then
\\[\\simplify[std]{Diff(u/v,x,1) = (v * Diff(u,x,1) - u * Diff(v,x,1))/v^2}\\]

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For this example:

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\\[\\simplify[std]{u = ({a}x^2+{b})}\\Rightarrow \\simplify[std]{Diff(u,x,1) = {2*a}x}\\]

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\\[\\simplify[std]{v = ({c} * x^2+{d})} \\Rightarrow \\simplify[std]{Diff(v,x,1) = {2*c}x}\\]

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Hence on substituting into the quotient rule above we get:

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\\[\\begin{eqnarray*} \\frac{df}{dx}&=&\\simplify[std]{({2*a}x({c}x^2+{d})-{2*c}x({a}x^2+{b}))/({c}x^2+{d})^2}\\\\\n \n &=&\\simplify[std]{({2*a*c}x^3+{2*a*d}x-{2*c*a}x^3-{2*c*b}x)/({c}x^2+{d})^2}\\\\\n \n &=&\\simplify[std]{({2*det}x)/({c}x^2+{d})^2}\n \n \\end{eqnarray*}\\]
Hence $g(x)=\\simplify[std]{{2*det}x}$

\n \n \n ", "preamble": {"css": "", "js": ""}, "question_groups": [{"questions": [], "pickingStrategy": "all-ordered", "pickQuestions": 0, "name": ""}], "name": "Luis's copy of Quotient rule - differentiate quadratic over quadratic", "variable_groups": [], "type": "question", "functions": {}, "variablesTest": {"maxRuns": 100, "condition": ""}, "statement": "

Differentiate the following function $f(x)$ using the quotient rule.

", "parts": [{"prompt": "\n

\\[\\simplify[std]{f(x) = ({a} * x^2+{b})/({c}x^2+{d})}\\]
You are given that \\[\\frac{df}{dx}=\\simplify[std]{g(x)/({c}x^2+{d})^2}\\]
for a polynomial $g(x)$. You are asked to find $g(x)$

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$g(x)=\\;$[[0]]

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Input numbers as fractions or integers and not as decimals.

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Click on Show steps for more information. You will not lose any marks by doing so.

\n ", "steps": [{"prompt": "

The quotient rule says that if $u$ and $v$ are functions of $x$ then
\\[\\simplify[std]{Diff(u/v,x,1) = (v * Diff(u,x,1) - u * Diff(v,x,1))/v^2}\\]

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Input numbers as fractions or integers and not as decimals.

", "partialCredit": 0, "strings": ["."]}, "expectedvariablenames": [], "marks": 3, "showCorrectAnswer": true, "checkingaccuracy": 0.001, "vsetrange": [0, 1], "showpreview": true, "answer": "{2*det}x", "vsetrangepoints": 5}], "stepsPenalty": 0, "type": "gapfill", "showCorrectAnswer": true, "marks": 0}], "ungrouped_variables": ["a", "c", "b", "d", "s2", "s1", "det", "c1"], "metadata": {"notes": "\n \t\t

1/08/2012:

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Added tags.

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Added description.

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Checked calculation. OK.

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Added information about Show steps. Altered to 0 marks lost rather than 1.

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Changed std rule set to include !noLeadingMinus, so polynomials don't change order. Got rid of a redundant ruleset.

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Improved display in various places.

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Added condition that numbers have to be inout as fractions or integers - added decimal point to forbidden strings.

\n \t\t", "description": "

The derivative of $\\displaystyle \\frac{ax^2+b}{cx^2+d}$ is $\\displaystyle \\frac{g(x)}{(cx^2+d)^2}$. Find $g(x)$.

", "licence": "Creative Commons Attribution 4.0 International"}, "tags": ["algebraic manipulation", "Calculus", "checked2015", "derivative of a quotient", "differentiation", "MAS1601", "quotient rule", "Steps"], "showQuestionGroupNames": false, "rulesets": {"std": ["all", "!collectNumbers", "fractionNumbers", "!noLeadingMinus"]}, "variables": {"c": {"templateType": "anything", "group": "Ungrouped variables", "description": "", "name": "c", "definition": "if(a*d=b*c1,c1+1,c1)"}, "b": {"templateType": "anything", "group": "Ungrouped variables", "description": "", "name": "b", "definition": "s1*random(1..9)"}, "s1": {"templateType": "anything", "group": "Ungrouped variables", "description": "", "name": "s1", "definition": "random(1,-1)"}, "d": {"templateType": "anything", "group": "Ungrouped variables", "description": "", "name": "d", "definition": "s2*random(1..9)"}, "s2": {"templateType": "anything", "group": "Ungrouped variables", "description": "", "name": "s2", "definition": "random(1,-1)"}, "det": {"templateType": "anything", "group": "Ungrouped variables", "description": "", "name": "det", "definition": "a*d-b*c"}, "c1": {"templateType": "anything", "group": "Ungrouped variables", "description": "", "name": "c1", "definition": "random(1..8)"}, "a": {"templateType": "anything", "group": "Ungrouped variables", "description": "", "name": "a", "definition": "random(2..9)"}}, "contributors": [{"name": "Newcastle University Mathematics and Statistics", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/697/"}, {"name": "Luis Hernandez", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/2870/"}]}]}], "contributors": [{"name": "Newcastle University Mathematics and Statistics", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/697/"}, {"name": "Luis Hernandez", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/2870/"}]}