// Numbas version: exam_results_page_options {"name": "T6Q9 (custom feedback)", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"parts": [{"variableReplacementStrategy": "originalfirst", "prompt": "

$\\frac{\\partial K}{\\partial r} =$ [[0]]

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", "showCorrectAnswer": true, "sortAnswers": false, "type": "gapfill", "unitTests": [], "customMarkingAlgorithm": "", "scripts": {}, "variableReplacements": [], "showFeedbackIcon": true, "marks": 0, "gaps": [{"variableReplacementStrategy": "originalfirst", "failureRate": 1, "checkVariableNames": false, "showPreview": true, "vsetRange": [0, 1], "type": "jme", "showCorrectAnswer": true, "checkingType": "absdiff", "checkingAccuracy": 0.001, "unitTests": [], "customMarkingAlgorithm": "malrules:\n [\n [\"15(r+s)^2*(r-s)^4\", \"There are two things to watch here. Firstly, don't forget the product rule! Since this is one function of $s$ multiplied by another function of $s$, you need the product rule. Secondly, when differentiating the $(r-s)^5$ term, don't forget to multiply by $\\\\frac{\\\\partial}{\\\\partial s} \\\\left( r-s \\\\right)$.\"],\n [\"-15(r+s)^2*(r-s)^4\", \"Don't forget the product rule! Since this is one function of $s$ multiplied by another function of $s$, you need the product rule.\"],\n [\"3(r+s)^2*(r-s)^5+5(r+s)^3*(r-s)^4\", \"Almost there. When differentiating the $(r-s)^5$ term, don't forget to multiply by $\\\\frac{\\\\partial}{\\\\partial s} \\\\left( r-s \\\\right)$.\"]\n ]\n\n\nparsed_malrules: \n map(\n [\"expr\":parse(x[0]),\"feedback\":x[1]],\n x,\n malrules\n )\n\nagree_malrules (Do the student's answer and the expected answer agree on each of the sets of variable values?):\n map(\n len(filter(not x ,x,map(\n try(\n resultsEqual(unset(question_definitions,eval(studentexpr,vars)),unset(question_definitions,eval(malrule[\"expr\"],vars)),settings[\"checkingType\"],settings[\"checkingAccuracy\"]),\n message,\n false\n ),\n vars,\n vset\n )))Partial differentiation question with customised feedback to catch some common errors.

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Let $K=(r+s)^3(r-s)^5$. Find $\\frac{\\partial K}{\\partial r}$ and $\\frac{\\partial K}{\\partial s}$.

", "type": "question", "contributors": [{"name": "Clodagh Carroll", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/384/"}]}]}], "contributors": [{"name": "Clodagh Carroll", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/384/"}]}