// Numbas version: exam_results_page_options
{"name": "Alan's copy of Graph of a quadratic function", "extensions": ["jsxgraph"], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"metadata": {"licence": "Creative Commons Attribution 4.0 International", "description": "<p>Compute a table of values for a quadratic function. A JSXgraph plot shows the curve going through the entered values.</p>"}, "extensions": ["jsxgraph"], "variables": {"x_2": {"templateType": "anything", "definition": "random(-4..4 except 0)", "description": "", "name": "x_2", "group": "Ungrouped variables"}, "x_1": {"templateType": "anything", "definition": "random(-2..2)", "description": "", "name": "x_1", "group": "Ungrouped variables"}}, "variablesTest": {"maxRuns": 100, "condition": ""}, "parts": [{"showCorrectAnswer": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "marks": 0, "scripts": {}, "extendBaseMarkingAlgorithm": true, "customMarkingAlgorithm": "", "unitTests": [], "showFeedbackIcon": true, "type": "gapfill", "prompt": "<p>Fill in the table of values for $y=\\simplify[std]{x^2+{x_1+x_2}x+{x_1}*{x_2}}$:</p>\n<table id=\"values\">\n<thead>\n<tr>\n<th>$x$</th>\n<th>$-3$</th>\n<th>$-2$</th>\n<th>$-1$</th>\n<th>$0$</th>\n<th>$1$</th>\n<th>$2$</th>\n<th>$3$</th>\n</tr>\n</thead>\n<tbody>\n<tr>\n<th>$y$</th>\n<td>[[0]]</td>\n<td>[[1]]</td>\n<td>[[2]]</td>\n<td>[[3]]</td>\n<td>[[4]]</td>\n<td>[[5]]</td>\n<td>[[6]]</td>\n</tr>\n</tbody>\n</table>\n<div id=\"dragpoint\"></div>", "gaps": [{"vsetRange": [0, 1], "vsetRangePoints": 5, "showCorrectAnswer": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "marks": 0.5, "scripts": {}, "checkingType": "absdiff", "extendBaseMarkingAlgorithm": true, "customMarkingAlgorithm": "", "answer": "{a}*9+{c}", "showFeedbackIcon": true, "checkingAccuracy": 0.001, "type": "jme", "checkVariableNames": false, "failureRate": 1, "unitTests": [], "showPreview": true, "expectedVariableNames": []}, {"vsetRange": [0, 1], "vsetRangePoints": 5, "showCorrectAnswer": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "marks": 0.5, "scripts": {}, "checkingType": "absdiff", "extendBaseMarkingAlgorithm": true, "customMarkingAlgorithm": "", "answer": "{a}*4+{c}", "showFeedbackIcon": true, "checkingAccuracy": 0.001, "type": "jme", "checkVariableNames": false, "failureRate": 1, "unitTests": [], "showPreview": true, "expectedVariableNames": []}, {"vsetRange": [0, 1], "vsetRangePoints": 5, "showCorrectAnswer": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "marks": 0.5, "scripts": {}, "checkingType": "absdiff", "extendBaseMarkingAlgorithm": true, "customMarkingAlgorithm": "", "answer": "{a}*1+{c}", "showFeedbackIcon": true, "checkingAccuracy": 0.001, "type": "jme", "checkVariableNames": false, "failureRate": 1, "unitTests": [], "showPreview": true, "expectedVariableNames": []}, {"vsetRange": [0, 1], "vsetRangePoints": 5, "showCorrectAnswer": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "marks": 0.5, "scripts": {}, "checkingType": "absdiff", "extendBaseMarkingAlgorithm": true, "customMarkingAlgorithm": "", "answer": "{c}", "showFeedbackIcon": true, "checkingAccuracy": 0.001, "type": "jme", "checkVariableNames": false, "failureRate": 1, "unitTests": [], "showPreview": true, "expectedVariableNames": []}, {"vsetRange": [0, 1], "vsetRangePoints": 5, "showCorrectAnswer": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "marks": 0.5, "scripts": {}, "checkingType": "absdiff", "extendBaseMarkingAlgorithm": true, "customMarkingAlgorithm": "", "answer": "{a}*1+{c}", "showFeedbackIcon": true, "checkingAccuracy": 0.001, "type": "jme", "checkVariableNames": false, "failureRate": 1, "unitTests": [], "showPreview": true, "expectedVariableNames": []}, {"vsetRange": [0, 1], "vsetRangePoints": 5, "showCorrectAnswer": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "marks": 0.5, "scripts": {}, "checkingType": "absdiff", "extendBaseMarkingAlgorithm": true, "customMarkingAlgorithm": "", "answer": "{a}*4+{c}", "showFeedbackIcon": true, "checkingAccuracy": 0.001, "type": "jme", "checkVariableNames": false, "failureRate": 1, "unitTests": [], "showPreview": true, "expectedVariableNames": []}, {"vsetRange": [0, 1], "vsetRangePoints": 5, "showCorrectAnswer": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "marks": 0.5, "scripts": {}, "checkingType": "absdiff", "extendBaseMarkingAlgorithm": true, "customMarkingAlgorithm": "", "answer": "{a}*9+{c}", "showFeedbackIcon": true, "checkingAccuracy": 0.001, "type": "jme", "checkVariableNames": false, "failureRate": 1, "unitTests": [], "showPreview": true, "expectedVariableNames": []}], "sortAnswers": false}], "advice": "", "variable_groups": [], "name": "Alan's copy of Graph of a quadratic function", "functions": {}, "statement": "<p>You are given the quadratic formula</p>\n<p>$y=\\simplify[std]{{a}x^2+{c}}$</p>", "tags": [], "rulesets": {"std": ["all", "fractionNumbers"]}, "preamble": {"js": "function dragpoint_board() {\n  var scope = question.scope;\n  \n  var x_1 = scope.variables.x_1.value;\n  var x_2 = scope.variables.x_2.value;\n  var maxy = Math.max((-5-x_1)*(-5-x_2),(5-x_1)*(5-x_2));\n  var miny = -[(x_1+x_2)/2]^2+x_1*x_2-3;\n  \n  var div = Numbas.extensions.jsxgraph.makeBoard('250px','400px',{boundingBox:[-5,maxy,5,miny],grid:true});\n  $(question.display.html).find('#dragpoint').append(div);\n  \n  var board = div.board;\n  \n  //shorthand to evaluate a mathematical expression to a number\n  function evaluate(expression) {\n    try {\n      var val = Numbas.jme.evaluate(expression,question.scope);\n      return Numbas.jme.unwrapValue(val);\n    }\n    catch(e) {\n      // if there's an error, return no number\n      return NaN;\n    }\n  }\n  \n  // set up points array\n  var num_points = 7;\n  var points = [];\n  \n  \n  // this function sets up the i^th point\n  function make_point(i) {\n    \n    // calculate initial coordinates\n    var x = i-(num_points-1)/2;\n    \n    // create an invisible vertical line for the point to slide along\n    var line = board.create('line',[[x,0],[x,1]],{visible: false});\n    \n    // create the point\n    var point = points[i] = board.create(\n      'glider',\n      [i-(num_points-1)/2,0,line],\n      {\n        name:'',\n        size:2,\n        snapSizeY: 0.1,  // the point will snap to y-coordinates which are multiples of 0.1\n        snapToGrid: true\n      }\n    );\n    \n    // the contents of the input box for this point\n    var studentAnswer = question.parts[1].gaps[i].display.studentAnswer;\n    \n    // watch the student's input and reposition the point when it changes.    \n    ko.computed(function() {\n      y = evaluate(studentAnswer());\n      if(!(isNaN(y)) && board.mode!=board.BOARD_MODE_DRAG) {\n        point.moveTo([x,y],100);\n      }\n    });\n    \n    // when the student drags the point, update the gapfill input\n    point.on('drag',function(){\n      var y = Numbas.math.niceNumber(point.Y());\n      studentAnswer(y);\n    });\n    \n  }\n  \n  // create each point\n  for(var i=0;i<num_points;i++) {\n    make_point(i);\n  }\n  \n  // create the parabola\n  var parabool = board.create('spline',points,{strokeWidth:3,strokeColor:'red'});\n}\n\nquestion.signals.on('HTMLAttached',function() {\n  dragpoint_board();\n}); ", "css": "table#values th {\n  background: none;\n  text-align: center;\n}"}, "ungrouped_variables": ["x_2", "x_1"], "type": "question", "contributors": [{"name": "Christian Lawson-Perfect", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/7/"}, {"name": "Maths Tutor", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/2680/"}]}]}], "contributors": [{"name": "Christian Lawson-Perfect", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/7/"}, {"name": "Maths Tutor", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/2680/"}]}