// Numbas version: finer_feedback_settings {"name": "Surds 2", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"functions": {}, "ungrouped_variables": ["a1", "a2", "a3", "b1", "b2", "b3", "c1", "c2", "d1", "d2", "d3", "d4", "e1", "e2", "e3", "e4", "e5", "f1", "f2", "f3", "f4", "f5", "f6", "f7", "f8"], "name": "Surds 2", "tags": [], "preamble": {"css": "fraction {\n display: inline-block;\n vertical-align: middle;\n}\nfraction > numerator, fraction > denominator {\n float: left;\n width: 100%;\n text-align: center;\n line-height: 2.5em;\n}\nfraction > numerator {\n border-bottom: 1px solid;\n padding-bottom: 5px;\n}\nfraction > denominator {\n padding-top: 5px;\n}\nfraction input {\n line-height: 1em;\n}\n\nfraction .part {\n margin: 0;\n}\n\n.table-responsive, .fractiontable {\n display:inline-block;\n}\n.fractiontable {\n padding: 0; \n border: 0;\n}\n\n.fractiontable .tddenom \n{\n text-align: center;\n}\n\n.fractiontable .tdnum \n{\n border-bottom: 1px solid black; \n text-align: center;\n}\n\n\n.fractiontable tr {\n height: 3em;\n}", "js": "document.createElement('fraction');\ndocument.createElement('numerator');\ndocument.createElement('denominator');"}, "advice": "
The best approach here is to first rationalise the denominator. We do this by multiplying both top and bottom by an approriate value.
\nFor example to rationalise the denominator for an expression like $\\frac{a}{\\sqrt{b}}$, we multiply numerator and denominator by $\\sqrt{b}$ to get $\\frac{a\\sqrt{b}}{b}$
\nSimilarly to rationalise the denominator for an expression like $\\frac{a+\\sqrt{b}}{c+\\sqrt{d}}$, we multiply numerator and denominator by $c-\\sqrt{d}$ to get $\\frac{(a+\\sqrt{b})(c-\\sqrt{d})}{c^2-d}$
\nDont forget that:
\n$\\sqrt{a \\times b} = \\sqrt{a} \\times \\sqrt{b}$
\n$\\sqrt{\\frac{a}{b}} = \\frac{\\sqrt{a}}{\\sqrt{b}}$
\n$(a+\\sqrt{b})(a-\\sqrt{b})=a^2-b$
\nRemember to check that your answer is in its simplest form.
", "rulesets": {}, "parts": [{"prompt": "$\\frac{\\var{a1}}{\\sqrt{\\var{a2}}}=$
$\\frac{\\var{b1}}{\\sqrt{\\var{b2}}}=$
$\\frac{\\var{c1}}{\\sqrt{\\var{c2}}}=$
$\\frac{\\var{d4}\\sqrt{\\var{d1}}}{\\sqrt{\\var{d2}}}=$
$\\frac{\\var{e1}\\sqrt{\\var{e2}}}{\\var{e3}\\sqrt{\\var{e4}}}=$
$\\frac{\\var{f1}\\sqrt{\\var{f6}}}{\\var{f2}\\sqrt{\\var{f5}}}=$
Express each of the following in the form $\\frac{a\\sqrt{b}}{c}$ where a, b and c are integers, where a and c have no common factors
", "variable_groups": [], "variablesTest": {"maxRuns": 100, "condition": "gcd({c1},{c2})=1"}, "variables": {"f1": {"definition": "random(2..5)", "templateType": "anything", "group": "Ungrouped variables", "name": "f1", "description": ""}, "f2": {"definition": "random(2..5 except f1)", "templateType": "anything", "group": "Ungrouped variables", "name": "f2", "description": ""}, "f3": {"definition": "random([2,3,5,7,11,13] except f2 except f1)", "templateType": "anything", "group": "Ungrouped variables", "name": "f3", "description": ""}, "f4": {"definition": "random([2,3,5,7] except f1 except f2 except f3)", "templateType": "anything", "group": "Ungrouped variables", "name": "f4", "description": ""}, "f5": {"definition": "f3*f1*f1", "templateType": "anything", "group": "Ungrouped variables", "name": "f5", "description": ""}, "f6": {"definition": "f8*f2*f2", "templateType": "anything", "group": "Ungrouped variables", "name": "f6", "description": ""}, "f7": {"definition": "random([4,9,16] except f3)", "templateType": "anything", "group": "Ungrouped variables", "name": "f7", "description": ""}, "f8": {"definition": "f4*f7", "templateType": "anything", "group": "Ungrouped variables", "name": "f8", "description": ""}, "b1": {"definition": "random(2..19)", "templateType": "anything", "group": "Ungrouped variables", "name": "b1", "description": ""}, "b2": {"definition": "random(2,3,5,6,7,10,11,13,14,15,17,19,21,23,22,26,29)", "templateType": "anything", "group": "Ungrouped variables", "name": "b2", "description": ""}, "b3": {"definition": "gcd(b2,b1)", "templateType": "anything", "group": "Ungrouped variables", "name": "b3", "description": ""}, "d4": {"definition": "random([4,6,10,12,14,20,22,26] except [2*d1])", "templateType": "anything", "group": "Ungrouped variables", "name": "d4", "description": ""}, "d2": {"definition": "d4/2", "templateType": "anything", "group": "Ungrouped variables", "name": "d2", "description": ""}, "d3": {"definition": "gcd(d4,d2)", "templateType": "anything", "group": "Ungrouped variables", "name": "d3", "description": ""}, "d1": {"definition": "random([2,3,5,7,11,13,17,19,23,29] except [c1])", "templateType": "anything", "group": "Ungrouped variables", "name": "d1", "description": ""}, "a1": {"definition": "random(2..19)", "templateType": "anything", "group": "Ungrouped variables", "name": "a1", "description": ""}, "a3": {"definition": "gcd(a1,a2)", "templateType": "anything", "group": "Ungrouped variables", "name": "a3", "description": ""}, "a2": {"definition": "random(2,3,5,6,7,10,11,13,14,15,17,19,21,23,22,26,29)", "templateType": "anything", "group": "Ungrouped variables", "name": "a2", "description": ""}, "e5": {"definition": "gcd(e1,e3*e4)", "templateType": "anything", "group": "Ungrouped variables", "name": "e5", "description": ""}, "e4": {"definition": "random([2,3,5,7] except [e2])", "templateType": "anything", "group": "Ungrouped variables", "name": "e4", "description": ""}, "c1": {"definition": "random(2,3,5,7,11,13,17,19,23,29)", "templateType": "anything", "group": "Ungrouped variables", "name": "c1", "description": ""}, "e1": {"definition": "random(2..9)", "templateType": "anything", "group": "Ungrouped variables", "name": "e1", "description": ""}, "e3": {"definition": "random(2..9)", "templateType": "anything", "group": "Ungrouped variables", "name": "e3", "description": ""}, "e2": {"definition": "random([2,3,5,7])", "templateType": "anything", "group": "Ungrouped variables", "name": "e2", "description": ""}, "c2": {"definition": "random([2,3,5,7,11,13,17,19,23,29] except [c1])", "templateType": "anything", "group": "Ungrouped variables", "name": "c2", "description": ""}}, "metadata": {"notes": "", "description": "", "licence": "Creative Commons Attribution 4.0 International"}, "type": "question", "showQuestionGroupNames": false, "question_groups": [{"name": "", "pickingStrategy": "all-ordered", "pickQuestions": 0, "questions": []}], "contributors": [{"name": "joshua boddy", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/557/"}]}]}], "contributors": [{"name": "joshua boddy", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/557/"}]}