// Numbas version: exam_results_page_options {"name": "T6Q1 (custom feedback)", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"name": "T6Q1 (custom feedback)", "tags": [], "metadata": {"description": "

Partial differentiation question with customised feedback to catch some common errors.

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Let $z=3xy+x^2-2y^3$. Find:

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$\\displaystyle \\frac{\\partial z}{\\partial x} = $ [[0]]

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", "gaps": [{"type": "jme", "useCustomName": false, "customName": "", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "malrules:\n [\n [\"3y+3x+2x-6y^2\", \"The product rule is not needed to differentiate $3xy$. Remember, when partially differentiating with respect to $y$, treat $x$ as a number. This also goes for the second term: $x^2$ is just treated as a number.\"],\n [\"(-3y-2x)/(3x-6y^2)\", \"It looks like you have used implicit differentiation rather than partial differentiation. Implicit differentiation is only used if you wish to find $\\\\frac{dy}{dx}$, not if you wish to find $\\\\frac{\\\\partial y}{\\\\partial x}$ or $\\\\frac{\\\\partial z}{\\\\partial y}$ etc.\"]\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 )))Now consider $40=3xy+x^2-2y^3$. Find $\\displaystyle \\frac{dy}{dx}$.

\n

$\\displaystyle \\frac{dy}{dx} =$ [[0]]

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