// Numbas version: finer_feedback_settings
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For example, <code>[1,2]</code>.');\n  return false;\n}\nreturn true;"}, "mark": {"order": "instead", "script": "// evaluate the student's answer\ntry {\n  var list = Numbas.jme.evaluate(this.studentAnswer,this.question.scope);\n}\ncatch(e)\n{\n  this.setCredit(0,R('part.jme.answer invalid',e.message));\n  return;\n}\n\n// check the answer is a list\nthis.notAList = list.type!='list';\nif(this.notAList) {\n  this.setCredit(0,'Your answer is not a list of numbers.');\n  return;\n}\n\nvar variables = this.question.scope.variables;\nvar unwrap = Numbas.jme.unwrapValue;\n\n// get the roots of the equation\nvar roots = unwrap(variables.roots);\n\n// unwrap the student's list to a Javascript array of numbers\nvar list = unwrap(list);\n\n// get the coefficients of the equation\nvar ea = unwrap(variables.ea);\nvar eb = unwrap(variables.eb);\nvar ec = unwrap(variables.ec);\n\n// check each root the student gave, keeping track of how many they got right\nvar got = 0;\nvar wrong = [];\nfor(var i=0;i<list.length;i++) {\n  var n = list[i];\n  if(roots.contains(n)) {\n     got += 1;\n  } else {\n    var total = ea*n*n+eb*n+ec;\n    this.markingComment('$\\\\simplify[fractionnumbers]{'+n+'}$ is not a root of the equation. On substituting $x = \\\\simplify[fractionnumbers]{'+n+'}$ into the equation, you should get $0$. \\\\[ \\\\simplify[fractionnumbers]{{ea}*('+n+'^2)+{eb}*('+n+')+{ec} = '+total+'} \\\\]');\n  }\n}\n\n// check if the student missed any roots\nvar notgot = 0;\nlist.sort();\nroots.sort();\nfor(var i=0;i<roots.length;i++) {\n  var n = roots[i];\n  if(!list.contains(n)) {\n    got -= 1;\n    this.markingComment(\"You did not give the root $\\\\simplify[fractionnumbers]{\"+n+\"}$.\");\n  }\n}\n\n// Give feedback\nif(list.length>roots.length) {\n  this.setCredit(0,\"This equation does not have \"+(list.length)+\" real-valued \"+Numbas.util.pluralise(list.length,'root','roots')+\".\");\n} else if(got<roots.length) {\n  this.setCredit(got/roots.length, \"You did not give every real-valued root of the equation.\");\n} else {\n  var message;\n  switch(roots.length) {\n    case 0:\n      message = \"Correct: this equation does not have any real-valued roots.\";\n      break;\n    case 1:\n      message = \"Correct: this equation has a repeated root.\";\n      break;\n    case 2:\n      message = \"You gave both roots of this equation.\";\n  }\n  this.setCredit(1,message);\n}"}}, "vsetrange": [0, 1], "variableReplacements": [], "type": "jme", "checkingtype": "absdiff", "answer": "{roots}", "checkvariablenames": false, "showCorrectAnswer": true, "showpreview": true, "answersimplification": "fractionNumbers", "prompt": "<p>Give the set of real-valued roots of the equation&nbsp;</p>\n<p>\\[ \\simplify[all,fractionnumbers]{{ea}x^2+{eb}x+{ec}}=0 \\]</p>\n<p>Enter your answer as a list of numbers separated by commas and enclosed by square brackets, e.g. <code>[1,2]</code>.</p>\n<p>If the equation has no roots, enter <code>[]</code></p>", "variableReplacementStrategy": "originalfirst", "marks": 2, "checkingaccuracy": 0.001}], "advice": "", "metadata": {"licence": "Creative Commons Attribution 4.0 International", "description": ""}, "rulesets": {}, "statement": "", "name": "Sharon's copy of Custom marking - answer is a set", "variablesTest": {"condition": "", "maxRuns": 100}, "tags": [], "variables": {"det": {"group": "Ungrouped variables", "templateType": "anything", "definition": "random(0..3)*random(1,i)", "description": "", "name": "det"}, "qb": {"group": "Ungrouped variables", "templateType": "anything", "definition": "random(-3..3)", "description": "", "name": "qb"}, "ea": {"group": "Ungrouped variables", "templateType": "anything", "definition": "f", "description": "", "name": "ea"}, "f": {"group": "Ungrouped variables", "templateType": "anything", "definition": "if(odds=0,1,4)", "description": "", "name": "f"}, "x0": {"group": "Ungrouped variables", "templateType": "anything", "definition": "(-qb+det)/2", "description": "", "name": "x0"}, "x1": {"group": "Ungrouped variables", "templateType": "anything", "definition": "(-qb-det)/2", "description": "", "name": "x1"}, "ec": {"group": "Ungrouped variables", "templateType": "anything", "definition": "x0*x1*f", "description": "", "name": "ec"}, "roots": {"group": "Ungrouped variables", "templateType": "anything", "definition": "if(im(det)<>0,[],if(det=0,[x0],[x0,x1]))", "description": "", "name": "roots"}, "eb": {"group": "Ungrouped variables", "templateType": "anything", "definition": "-f*(x0+x1)", "description": "", "name": "eb"}, "odds": {"group": "Ungrouped variables", "templateType": "anything", "definition": "mod(im(qb+det),2)+mod(re(qb+det),2)", "description": "", "name": "odds"}}, "variable_groups": [], "preamble": {"css": "", "js": ""}, "type": "question", "contributors": [{"name": "Sharon Gardner", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/1313/"}]}]}], "contributors": [{"name": "Sharon Gardner", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/1313/"}]}