// Numbas version: exam_results_page_options
{"name": "Ricardo's copy of Custom marking - answer is a set", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"functions": {}, "ungrouped_variables": ["f", "ea", "odds", "det", "ec", "eb", "qb", "x0", "x1", "roots"], "name": "Ricardo's copy of Custom marking - answer is a set", "tags": ["custom marking", "demo"], "type": "question", "advice": "", "rulesets": {}, "parts": [{"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>", "expectedvariablenames": [], "checkingaccuracy": 0.001, "type": "jme", "showpreview": true, "vsetrangepoints": 5, "showCorrectAnswer": true, "answersimplification": "fractionNumbers", "scripts": {"validate": {"order": "instead", "script": "// Use the built-in validation function to catch syntax errors and so on\nif(!JMEPart.prototype.validate.apply(this)) {\n  return false;\n}\n// Give a warning if the student's answer is not a list\nif(this.notAList) {\n  this.giveWarning('You must enter a list, i.e. numbers separated by commas and enclosed by square brackets. 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}"}}, "answer": "{roots}", "marks": 2, "checkvariablenames": false, "checkingtype": "absdiff", "vsetrange": [0, 1]}], "statement": "", "variable_groups": [], "variablesTest": {"maxRuns": 100, "condition": ""}, "preamble": {"css": "", "js": ""}, "variables": {"f": {"definition": "if(odds=0,1,4)", "templateType": "anything", "group": "Ungrouped variables", "name": "f", "description": ""}, "ea": {"definition": "f", "templateType": "anything", "group": "Ungrouped variables", "name": "ea", "description": ""}, "odds": {"definition": "mod(im(qb+det),2)+mod(re(qb+det),2)", "templateType": "anything", "group": "Ungrouped variables", "name": "odds", "description": ""}, "det": {"definition": "random(0..3)*random(1,i)", "templateType": "anything", "group": "Ungrouped variables", "name": "det", "description": ""}, "ec": {"definition": "x0*x1*f", "templateType": "anything", "group": "Ungrouped variables", "name": "ec", "description": ""}, "eb": {"definition": "-f*(x0+x1)", "templateType": "anything", "group": "Ungrouped variables", "name": "eb", "description": ""}, "qb": {"definition": "random(-3..3)", "templateType": "anything", "group": "Ungrouped variables", "name": "qb", "description": ""}, "x0": {"definition": "(-qb+det)/2", "templateType": "anything", "group": "Ungrouped variables", "name": "x0", "description": ""}, "x1": {"definition": "(-qb-det)/2", "templateType": "anything", "group": "Ungrouped variables", "name": "x1", "description": ""}, "roots": {"definition": "if(im(det)<>0,[],if(det=0,[x0],[x0,x1]))", "templateType": "anything", "group": "Ungrouped variables", "name": "roots", "description": ""}}, "metadata": {"notes": "", "description": "", "licence": "Creative Commons Attribution 4.0 International"}, "showQuestionGroupNames": false, "question_groups": [{"name": "", "pickingStrategy": "all-ordered", "pickQuestions": 0, "questions": []}], "contributors": [{"name": "Ricardo Monge", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/471/"}]}]}], "contributors": [{"name": "Ricardo Monge", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/471/"}]}