// Numbas version: finer_feedback_settings {"feedback": {"allowrevealanswer": true, "intro": "", "showtotalmark": true, "showactualmark": true, "showanswerstate": true, "feedbackmessages": [], "advicethreshold": 0, "enterreviewmodeimmediately": true, "showexpectedanswerswhen": "inreview", "showpartfeedbackmessageswhen": "always", "showactualmarkwhen": "always", "showtotalmarkwhen": "always", "showanswerstatewhen": "always", "showadvicewhen": "never"}, "navigation": {"allowregen": true, "browse": true, "reverse": true, "showfrontpage": true, "showresultspage": "oncompletion", "onleave": {"message": "", "action": "none"}, "preventleave": true}, "showQuestionGroupNames": false, "question_groups": [{"pickQuestions": 1, "name": "Group", "pickingStrategy": "all-ordered", "questions": [{"name": "Evaluate f(x)", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Frank Doheny", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/789/"}], "parts": [{"type": "gapfill", "variableReplacementStrategy": "originalfirst", "gaps": [{"maxValue": "{a1}*({a3}^{a2})+{b1}*{a3}-{c1}", "variableReplacements": [], "correctAnswerStyle": "plain", "notationStyles": ["plain", "en", "si-en"], "strictPrecision": false, "precisionType": "dp", "mustBeReducedPC": 0, "variableReplacementStrategy": "originalfirst", "precisionPartialCredit": 0, "correctAnswerFraction": false, "type": "numberentry", "showFeedbackIcon": true, "precisionMessage": "You have not given your answer to the correct precision.", "precision": "2", "minValue": "{a1}*({a3}^{a2})+{b1}*{a3}-{c1}", "showPrecisionHint": true, "allowFractions": false, "showCorrectAnswer": true, "scripts": {}, "mustBeReduced": false, "marks": 1}], "showFeedbackIcon": true, "prompt": "
Evaluate \\(f(\\var{a3})\\)
\n\\(f(\\var{a3})\\) = [[0]]
", "scripts": {}, "showCorrectAnswer": true, "variableReplacements": [], "marks": 0}], "rulesets": {}, "functions": {}, "ungrouped_variables": ["a1", "a2", "b1", "c1", "a3"], "metadata": {"licence": "Creative Commons Attribution 4.0 International", "description": "Evaluating a function
"}, "preamble": {"css": "", "js": ""}, "variable_groups": [], "tags": [], "variablesTest": {"maxRuns": 100, "condition": ""}, "variables": {"a1": {"definition": "random(2..12#1)", "description": "", "group": "Ungrouped variables", "name": "a1", "templateType": "randrange"}, "a3": {"definition": "random(1..6#1)", "description": "", "group": "Ungrouped variables", "name": "a3", "templateType": "randrange"}, "c1": {"definition": "random(1..15#1)", "description": "", "group": "Ungrouped variables", "name": "c1", "templateType": "randrange"}, "a2": {"definition": "random(2..5#1)", "description": "", "group": "Ungrouped variables", "name": "a2", "templateType": "randrange"}, "b1": {"definition": "random(3..12#1)", "description": "", "group": "Ungrouped variables", "name": "b1", "templateType": "randrange"}}, "advice": "\\(f(x)=\\var{a1}x^{\\var{a2}}+\\var{b1}x-\\var{c1}\\)
\n\\(x=\\var{a3}\\)
\n\\(f(\\var{a3})=\\var{a1}*(\\var{a3})^{\\var{a2}}+\\var{b1}*(\\var{a3})-\\var{c1}\\)
\n\\(f(\\var{a3})=\\simplify{{a1}*{a3}^{{a2}}}+\\simplify{{b1}*{a3}}-\\var{c1}\\)
\n\\(f(\\var{a3})=\\simplify{{a1}*{a3}^{{a2}}+{b1}*{a3}-{c1}}\\)
", "statement": "Given the function:
\n\\(f(x)=\\var{a1}x^{\\var{a2}}+\\var{b1}x-\\var{c1}\\)
", "type": "question"}, {"name": "Evaluate a limit", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Frank Doheny", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/789/"}], "functions": {}, "ungrouped_variables": ["a", "b"], "tags": [], "advice": "\\(\\displaystyle{\\lim_{x \\to \\var{a}}}\\frac{x-\\var{a}}{x^2-\\simplify{{a}+{b}}x+\\simplify{{a}*{b}}}\\)
\nWe can factorise the denominator
\n\\(\\displaystyle{\\lim_{x \\to \\var{a}}}\\frac{x-\\var{a}}{(x-\\var{a})(x-\\var{b})}\\)
\nCancel out the common factor
\n\\(\\displaystyle{\\lim_{x \\to \\var{a}}}\\frac{1}{x-\\var{b}}\\)
\nInsert the value \\(\\var{a}\\) in for \\(x\\) to evaluate the limit
\n\\(-\\frac{1}{\\simplify{{b}-{a}}}\\)
\n", "rulesets": {}, "parts": [{"prompt": "Input your answer as a fraction.
", "allowFractions": true, "variableReplacements": [], "maxValue": "1/({a}-{b})", "minValue": "1/({a}-{b})", "variableReplacementStrategy": "originalfirst", "correctAnswerFraction": true, "showCorrectAnswer": true, "scripts": {}, "marks": 1, "type": "numberentry"}], "statement": "Evaluate the following limit
\n\\(\\displaystyle{\\lim_{x \\to \\var{a}}}\\frac{x-\\var{a}}{x^2-\\simplify{{a}+{b}}x+\\simplify{{a}*{b}}}\\)
\n", "variable_groups": [], "variablesTest": {"maxRuns": 100, "condition": "aEvaluate a limit", "licence": "Creative Commons Attribution 4.0 International"}, "type": "question"}, {"name": "Solve an exponential equation", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Frank Doheny", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/789/"}], "advice": "\\(\\var{k}=\\var{a}e^{\\var{m}x+{\\var{c}}}\\)
\n\\(\\frac{\\var{k}}{\\var{a}}=e^{\\var{m}x+\\var{c}}\\)
\n\\(ln\\left(\\frac{\\var{k}}{\\var{a}}\\right)=\\var{m}x+\\var{c}\\)
\n\\(ln\\left(\\frac{\\var{k}}{\\var{a}}\\right)-\\var{c}=\\var{m}x\\)
\n\\(\\frac{ln\\left(\\frac{\\var{k}}{\\var{a}}\\right)-\\var{c}}{\\var{m}}=x\\)
", "metadata": {"licence": "Creative Commons Attribution 4.0 International", "description": "Solve an exponential equation
"}, "preamble": {"css": "", "js": ""}, "ungrouped_variables": ["a", "m", "c", "k"], "variable_groups": [], "functions": {}, "statement": "Given the equation \\(f(x)=\\var{a}e^{\\var{m}x+\\var{c}}\\)
\nDetermine the value for \\(x\\) that satisfies the relation \\(f(x)=\\var{k}\\)
", "tags": [], "rulesets": {}, "parts": [{"marks": 0, "prompt": "Input your answer correct to three decimal places.
\n\\(x = \\) [[0]]
", "showCorrectAnswer": true, "variableReplacementStrategy": "originalfirst", "showFeedbackIcon": true, "scripts": {}, "variableReplacements": [], "type": "gapfill", "gaps": [{"mustBeReducedPC": 0, "precisionPartialCredit": 0, "maxValue": "(ln({k}/{a})-{c})/{m}", "precision": "3", "strictPrecision": false, "precisionMessage": "You have not given your answer to the correct precision.", "correctAnswerFraction": false, "mustBeReduced": false, "variableReplacementStrategy": "originalfirst", "correctAnswerStyle": "plain", "type": "numberentry", "allowFractions": false, "precisionType": "dp", "notationStyles": ["plain", "en", "si-en"], "showCorrectAnswer": true, "showPrecisionHint": false, "marks": "2", "scripts": {}, "variableReplacements": [], "showFeedbackIcon": true, "minValue": "(ln({k}/{a})-{c})/{m}"}]}], "variables": {"a": {"templateType": "randrange", "group": "Ungrouped variables", "name": "a", "description": "", "definition": "random(4..20#1)"}, "c": {"templateType": "randrange", "group": "Ungrouped variables", "name": "c", "description": "", "definition": "random(0.1..3#0.2)"}, "m": {"templateType": "randrange", "group": "Ungrouped variables", "name": "m", "description": "", "definition": "random(0.1..1.5#0.1)"}, "k": {"templateType": "randrange", "group": "Ungrouped variables", "name": "k", "description": "", "definition": "random(100..150#1)"}}, "variablesTest": {"maxRuns": 100, "condition": "c>0 or c<0 "}, "type": "question"}, {"name": "Solve a logarithmic equation", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Frank Doheny", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/789/"}], "parts": [{"scripts": {}, "marks": 0, "variableReplacements": [], "type": "gapfill", "showCorrectAnswer": true, "prompt": "Calculate the value of \\(x\\) that satisfies the equation when \\(y=\\var{d}\\).
\nInput your answer correct to three decimal places.
\n\\(x = \\) [[0]]
", "showFeedbackIcon": true, "variableReplacementStrategy": "originalfirst", "gaps": [{"precisionPartialCredit": 0, "precisionMessage": "You have not given your answer to the correct precision.", "correctAnswerStyle": "plain", "scripts": {}, "maxValue": "((10^(d/a))-c)/b", "mustBeReduced": false, "showCorrectAnswer": true, "type": "numberentry", "variableReplacementStrategy": "originalfirst", "mustBeReducedPC": 0, "correctAnswerFraction": false, "allowFractions": false, "variableReplacements": [], "strictPrecision": false, "marks": "2", "minValue": "((10^(d/a))-c)/b", "precisionType": "dp", "showPrecisionHint": false, "showFeedbackIcon": true, "notationStyles": ["plain", "en", "si-en"], "precision": "3"}]}], "statement": "Given the following logarithmic equation:
\n\\(y=\\var{a}log(\\var{b}x+\\var{c}))\\)
\n", "rulesets": {}, "variable_groups": [], "ungrouped_variables": ["a", "b", "c", "d"], "functions": {}, "tags": [], "metadata": {"licence": "Creative Commons Attribution 4.0 International", "description": "Solve a logarithmic equation
"}, "variablesTest": {"condition": "", "maxRuns": 100}, "advice": "\\(\\var{a}log(\\var{b}x+\\var{c})=\\var{d}\\)
\nDivide across by \\(\\var{a}\\)
\n\\(log(\\var{b}x+\\var{c})=\\var{d}/\\var{a}=\\simplify{{d}/{a}}\\)
\n\\(\\var{b}x+\\var{c}=10^{\\simplify{{d}/{a}}}\\)
\n\\(\\var{b}x+\\var{c}=\\simplify{10^{{d}/{a}}}\\)
\n\\(\\var{b}x=\\simplify{10^{{d}/{a}}}-\\var{c}\\)
\n\\(\\var{b}x=\\simplify{10^{{d}/{a}}-{c}}\\)
\n\\(x=\\simplify{(10^{{d}/{a}}-{c})/{b}}\\)
", "preamble": {"css": "", "js": ""}, "variables": {"b": {"name": "b", "templateType": "randrange", "group": "Ungrouped variables", "description": "", "definition": "random(2..6#1)"}, "c": {"name": "c", "templateType": "randrange", "group": "Ungrouped variables", "description": "", "definition": "random(2..10#1)"}, "a": {"name": "a", "templateType": "randrange", "group": "Ungrouped variables", "description": "", "definition": "random(2..8#1)"}, "d": {"name": "d", "templateType": "randrange", "group": "Ungrouped variables", "description": "", "definition": "random(1..6#1)"}}, "type": "question"}, {"name": "Manipulation of formula 1", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Frank Doheny", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/789/"}], "metadata": {"description": "Manipulation of an exponential function
", "licence": "Creative Commons Attribution 4.0 International"}, "tags": [], "ungrouped_variables": ["k", "c", "m", "d"], "variables": {"c": {"description": "", "definition": "random(2..10#1)", "templateType": "randrange", "group": "Ungrouped variables", "name": "c"}, "m": {"description": "", "definition": "random(1.6..5#0.2)", "templateType": "randrange", "group": "Ungrouped variables", "name": "m"}, "k": {"description": "", "definition": "random(2..12#1)", "templateType": "randrange", "group": "Ungrouped variables", "name": "k"}, "d": {"description": "", "definition": "random(1..14#1)", "templateType": "randrange", "group": "Ungrouped variables", "name": "d"}}, "variable_groups": [], "variablesTest": {"condition": "", "maxRuns": 100}, "rulesets": {}, "parts": [{"type": "gapfill", "prompt": "\\(x =\\) [[0]]
", "scripts": {}, "showCorrectAnswer": true, "variableReplacementStrategy": "originalfirst", "gaps": [{"type": "jme", "answer": "(ln((1-y/{k})/{c})-{d})/{m}", "scripts": {}, "showpreview": true, "expectedvariablenames": [], "variableReplacementStrategy": "originalfirst", "vsetrangepoints": 5, "showFeedbackIcon": true, "checkvariablenames": false, "showCorrectAnswer": true, "variableReplacements": [], "checkingaccuracy": 0.001, "checkingtype": "absdiff", "vsetrange": [0, 1], "marks": "2"}], "marks": 0, "showFeedbackIcon": true, "variableReplacements": []}], "preamble": {"css": "", "js": ""}, "functions": {}, "advice": "\\(y=\\var{k}(1-\\var{c}e^{\\var{m}x+\\var{d}})\\)
\nWorking from the outside in, we divide across by \\(\\var{k}\\)
\n\\(\\frac{y}{\\var{k}}=1-\\var{c}e^{\\var{m}x+\\var{d}}\\)
\nWe can bring the \\(x\\) variable to the left hand side and move the \\(y\\) variable to the right hand side
\n\\(\\var{c}e^{\\var{m}x+\\var{d}}=1-\\frac{y}{\\var{k}}\\)
\nAgain working from the outside in we divide across by \\(\\var{c}\\)
\n\\(e^{\\var{m}x+\\var{d}}=\\frac{1-\\frac{y}{\\var{k}}}{\\var{c}}\\)
\nTaking the natural log of both sides eliminates the \\(e\\) from the left hand side.
\n\\(\\var{m}x+\\var{d}=ln\\left(\\frac{1-\\frac{y}{\\var{k}}}{\\var{c}}\\right)\\)
\nSubtract \\(\\var{d}\\) from both sides
\n\\(\\var{m}x=ln\\left(\\frac{1-\\frac{y}{\\var{k}}}{\\var{c}}\\right)-\\var{d}\\)
\nand finally divide by \\(\\var{m}\\) to get
\n\\(x=\\frac{ln\\left(\\frac{1-\\frac{y}{\\var{k}}}{\\var{c}}\\right)-\\var{d}}{\\var{m}}\\)
", "statement": "Rearrange the following expression to make \\(x\\) the subject:
\n\\(y=\\var{k}(1-\\var{c}e^{\\var{m}x+\\var{d}})\\)
", "type": "question"}, {"name": "Manipulation of formula 2", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Frank Doheny", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/789/"}], "metadata": {"description": "Manipulation of algebraic fractions
", "licence": "Creative Commons Attribution 4.0 International"}, "tags": [], "ungrouped_variables": ["a", "b", "c", "d"], "variables": {"c": {"description": "", "definition": "random(2..10#1)", "templateType": "randrange", "group": "Ungrouped variables", "name": "c"}, "b": {"description": "", "definition": "random(2..10#1)", "templateType": "randrange", "group": "Ungrouped variables", "name": "b"}, "a": {"description": "", "definition": "random(6..15#1)", "templateType": "randrange", "group": "Ungrouped variables", "name": "a"}, "d": {"description": "", "definition": "random(8..16#1)", "templateType": "randrange", "group": "Ungrouped variables", "name": "d"}}, "variable_groups": [], "variablesTest": {"condition": "{a}*{d}>{c}*{b}", "maxRuns": 100}, "rulesets": {}, "parts": [{"type": "gapfill", "prompt": "Express your answer as a fraction:
\n\\(V =\\) [[0]]
", "scripts": {}, "showCorrectAnswer": true, "variableReplacementStrategy": "originalfirst", "gaps": [{"type": "jme", "answer": "((5*{b}-{d})R+8)/(({a}*{d}-{b}*{c})R+7*{a}-3*{c})", "scripts": {}, "showpreview": true, "expectedvariablenames": [], "variableReplacementStrategy": "originalfirst", "vsetrangepoints": 5, "showFeedbackIcon": true, "checkvariablenames": false, "showCorrectAnswer": true, "variableReplacements": [], "checkingaccuracy": 0.001, "checkingtype": "absdiff", "vsetrange": [0, 1], "marks": "2"}], "marks": 0, "showFeedbackIcon": true, "variableReplacements": []}], "preamble": {"css": "", "js": ""}, "functions": {}, "advice": "When one fraction equals another fraction we can clear both fractions by cross-multiplying:
\n\\((\\var{a}V+1)*(\\var{d}R+7)=(\\var{b}R+3)*(\\var{c}V+5)\\)
\n\\(\\simplify{{a}*{d}}VR+\\simplify{7*{a}}V+\\var{d}R+7=\\simplify{{b}*{c}}VR+\\simplify{5*{b}}R+\\simplify{3*{c}}V+15\\)
\nGathering all the terms involving \\(V\\) to the left hand side and moving all other terms to the right hand side gives
\n\\(\\simplify{{a}*{d}-{b}*{c}}VR+\\simplify{7*{a}-3*{c}}V=\\simplify{5*{b}-{d}}R+8\\)
\nFactoring \\(V\\) out on the left hand side
\n\\(V(\\simplify{{a}*{d}-{b}*{c}}R+\\simplify{7*{a}-3*{c}})=\\simplify{5*{b}-{d}}R+8\\)
\nThus
\n\\(V=\\frac{\\simplify{5*{b}-{d}}R+8}{\\simplify{{a}*{d}-{b}*{c}}R+\\simplify{7*{a}-3*{c}}}\\)
", "statement": "Rearrange the following expression to make V the subject:
\n\\(\\frac{\\var{a}V+1}{\\var{b}R+3}=\\frac{\\var{c}V+5}{\\var{d}R+7}\\)
", "type": "question"}, {"name": "Solving quadratic equations 1(a)", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Frank Doheny", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/789/"}], "statement": "There are two values that satisfy the quadratic equation:
\n\\(\\var{a1}x^2+\\simplify{{{a1}*{b1}*{c1}}}=\\simplify{{a1}*{b1}+{a1}{c1}}x\\)
", "rulesets": {}, "variable_groups": [], "tags": [], "functions": {}, "parts": [{"scripts": {}, "marks": 0, "variableReplacements": [], "type": "gapfill", "showCorrectAnswer": true, "prompt": "Type in the greater of the two values that satisfies the equation.
\nInput your answer correct to three decimal places. \\(x = \\) [[0]]
\nType in the lesser of the two values that satisfies the equation.
\nInput your answer correct to three decimal places. \\(x = \\) [[1]]
", "showFeedbackIcon": true, "variableReplacementStrategy": "originalfirst", "gaps": [{"notationStyles": ["plain", "en", "si-en"], "precisionPartialCredit": 0, "correctAnswerStyle": "plain", "scripts": {}, "variableReplacements": [], "maxValue": "{b1}", "mustBeReduced": false, "precisionMessage": "You have not given your answer to the correct precision.", "showCorrectAnswer": true, "type": "numberentry", "variableReplacementStrategy": "originalfirst", "mustBeReducedPC": 0, "correctAnswerFraction": false, "allowFractions": false, "minValue": "{b1}", "marks": 1, "strictPrecision": false, "precisionType": "dp", "showPrecisionHint": false, "showFeedbackIcon": true, "precision": "3"}, {"notationStyles": ["plain", "en", "si-en"], "precisionPartialCredit": 0, "correctAnswerStyle": "plain", "scripts": {}, "variableReplacements": [], "maxValue": "{c1}", "mustBeReduced": false, "precisionMessage": "You have not given your answer to the correct precision.", "showCorrectAnswer": true, "type": "numberentry", "variableReplacementStrategy": "originalfirst", "mustBeReducedPC": 0, "correctAnswerFraction": false, "allowFractions": false, "minValue": "{c1}", "marks": 1, "strictPrecision": false, "precisionType": "dp", "showPrecisionHint": false, "showFeedbackIcon": true, "precision": "3"}]}], "metadata": {"licence": "Creative Commons Attribution 4.0 International", "description": "Solving quadratic equations using a formula,
"}, "variablesTest": {"condition": "", "maxRuns": "1"}, "advice": "The formula for solving a quadratic equation of the form \\(ax^2+bx+c=0\\) is given by
\n\\(x=\\frac{-b\\pm \\sqrt{b^2-4ac}}{2a}\\)
\nIn this example \\(a=\\var{a1},\\,\\,\\,b=\\simplify{+-{a1}*({b1}+{c1})}\\) and \\(c=\\simplify{{a1}*{b1}*{c1}}\\)
\n\\(x=\\frac{\\var{b}\\pm \\sqrt{(-\\var{b})^2-4*\\var{a1}*\\var{c}}}{2*\\var{a1}}\\)
\n\\(x=\\frac{\\var{b}\\pm \\sqrt{\\simplify{{b}^2-4*{a1}*{c}}}}{\\simplify{2*{a1}}}\\)
\n\\(x=\\simplify{{b}+({b}^2-4*{a1}*{c})^0.5}/\\simplify{2*{a1}}=\\simplify{({b}+({b}^2-4*{a1}*{c})^0.5)/(2*{a1})}\\) or \\(x=\\simplify{{b}-({b}^2-4*{a1}*{c})^0.5}/\\simplify{2*{a1}}=\\simplify{({b}-({b}^2-4*{a1}*{c})^0.5)/(2*{a1})}\\)
\n\n", "ungrouped_variables": ["a1", "b1", "c1", "b", "c"], "preamble": {"css": "", "js": ""}, "variables": {"b": {"name": "b", "templateType": "anything", "definition": "{a1}*({b1}+{c1})", "description": "", "group": "Ungrouped variables"}, "a1": {"name": "a1", "templateType": "randrange", "definition": "random(1..6#1)", "description": "", "group": "Ungrouped variables"}, "c": {"name": "c", "templateType": "anything", "definition": "{a1}*{b1}*{c1}", "description": "", "group": "Ungrouped variables"}, "b1": {"name": "b1", "templateType": "randrange", "definition": "random(11..25#1)", "description": "", "group": "Ungrouped variables"}, "c1": {"name": "c1", "templateType": "randrange", "definition": "random(1..10#1)", "description": "", "group": "Ungrouped variables"}}, "type": "question"}, {"name": "Solving quadratic equations 1(b)", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Frank Doheny", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/789/"}], "parts": [{"scripts": {}, "marks": 0, "variableReplacements": [], "showFeedbackIcon": true, "showCorrectAnswer": true, "prompt": "Type in the greater of the two values that satisfies the equation. Input your answer correct to three decimal places.
\n\\(x\\) = [[0]]
\nType in the lesser of the two values that satisfies the equation. Input your answer correct to three decimal places.
\n\\(x\\) = [[1]]
", "type": "gapfill", "variableReplacementStrategy": "originalfirst", "gaps": [{"precisionPartialCredit": 0, "precisionMessage": "You have not given your answer to the correct precision.", "correctAnswerStyle": "plain", "scripts": {}, "maxValue": "-{b1}/(2*{a1})+sqrt({b1}^2-4*{a1}*{c1})/(2*{a1})", "mustBeReduced": false, "showFeedbackIcon": true, "showCorrectAnswer": true, "type": "numberentry", "variableReplacementStrategy": "originalfirst", "mustBeReducedPC": 0, "correctAnswerFraction": false, "allowFractions": false, "strictPrecision": false, "marks": 1, "variableReplacements": [], "precisionType": "dp", "showPrecisionHint": false, "minValue": "-{b1}/(2*{a1})+sqrt({b1}^2-4*{a1}*{c1})/(2*{a1})", "notationStyles": ["plain", "en", "si-en"], "precision": "3"}, {"precisionPartialCredit": 0, "precisionMessage": "You have not given your answer to the correct precision.", "correctAnswerStyle": "plain", "scripts": {}, "maxValue": "-{b1}/(2*{a1})-sqrt({b1}^2-4*{a1}*{c1})/(2*{a1})", "mustBeReduced": false, "showFeedbackIcon": true, "showCorrectAnswer": true, "type": "numberentry", "variableReplacementStrategy": "originalfirst", "mustBeReducedPC": 0, "correctAnswerFraction": false, "allowFractions": false, "strictPrecision": false, "marks": 1, "variableReplacements": [], "precisionType": "dp", "showPrecisionHint": false, "minValue": "-{b1}/(2*{a1})-sqrt({b1}^2-4*{a1}*{c1})/(2*{a1})", "notationStyles": ["plain", "en", "si-en"], "precision": "3"}]}], "statement": "There are two values that satisfy the quadratic function below when \\(y=\\var{c1}\\):
\n\\(y=\\var{a1}x^2+\\var{b1}x\\)
", "rulesets": {}, "variable_groups": [], "ungrouped_variables": ["a1", "b1", "c1"], "functions": {}, "metadata": {"licence": "Creative Commons Attribution 4.0 International", "description": "Solving quadratic equations using a formula,
"}, "variablesTest": {"condition": "b1^2>4*a1*c1", "maxRuns": "1"}, "advice": "The formula for solving a quadratic equation of the form \\(ax^2+bx+c=0\\) is given by
\n\\(x=\\frac{-b\\pm \\sqrt{b^2-4ac}}{2a}\\)
\nIn this example \\(a=\\var{a1},\\,\\,\\,b=\\var{b1}\\) and \\(c=\\var{c1}\\)
\n\\(x=\\frac{-\\var{b1}\\pm \\sqrt{\\var{b1}^2-4\\times\\var{a1}\\times\\var{c1}}}{2\\times\\var{a1}}\\)
\n\\(x=\\frac{-\\var{b1}\\pm \\sqrt{\\simplify{{b1}^2-4*{a1}*{c1}}}}{\\simplify{2*{a1}}}\\)
\n\\(x=\\simplify{(-{b1}+ ({b1}^2-4*{a1}*{c1})^0.5)/(2*{a1})}\\) or \\(x=\\simplify{(-{b1}- ({b1}^2-4*{a1}*{c1})^0.5)/(2*{a1})}\\)
", "preamble": {"css": "", "js": ""}, "variables": {"a1": {"name": "a1", "templateType": "randrange", "group": "Ungrouped variables", "description": "", "definition": "random(1..6#1)"}, "b1": {"name": "b1", "templateType": "randrange", "group": "Ungrouped variables", "description": "", "definition": "random(16..25#1)"}, "c1": {"name": "c1", "templateType": "randrange", "group": "Ungrouped variables", "description": "", "definition": "random(1..10#1)"}}, "tags": [], "type": "question"}, {"name": "Solving quadratic equations 1(c)", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Frank Doheny", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/789/"}], "rulesets": {}, "functions": {}, "type": "question", "preamble": {"css": "", "js": ""}, "statement": "The following equation can be converted into a quadratic equation:
\n\\(\\var{a1}x+\\frac{\\simplify{{a1}*{b1}*{c1}}}{x}=\\simplify{{a1}*({b1}+{c1})}\\)
", "showQuestionGroupNames": false, "tags": [], "variable_groups": [], "variablesTest": {"maxRuns": "1", "condition": ""}, "metadata": {"licence": "Creative Commons Attribution 4.0 International", "description": "Solving quadratic equations using a formula
"}, "advice": "\\(\\var{a1}x+\\frac{\\simplify{{a1}*{b1}*{c1}}}{x}=\\simplify{{a1}*({b1}+{c1})}\\)
\nWe clear the fraction in the equation by multiplying across by \\(x\\)
\n\\(\\var{a1}x^2+\\simplify{{a1}*{b1}*{c1}}=\\simplify{{a1}*({b1}+{c1})}x\\)
\nBringing all the terms to the left hand side and putting them in order of their powers of \\(x\\) gives
\n\\(\\var{a1}x^2-\\simplify{{a1}*({b1}+{c1})}x+\\simplify{{a1}*{b1}*{c1}}=0\\)
\nThe formula for solving a quadratic equation of the form \\(ax^2+bx+c=0\\) is given by
\n\\(x=\\frac{-b\\pm \\sqrt{b^2-4ac}}{2a}\\)
\nIn this example \\(a=\\var{a1},\\,\\,\\,b=\\simplify{+-{a1}*({b1}+{c1})}\\) and \\(c=\\simplify{{a1}*{b1}*{c1}}\\)
\n\\(x=\\frac{\\var{b}\\pm \\sqrt{(-\\var{b})^2-4*\\var{a1}*\\var{c}}}{2*\\var{a1}}\\)
\n\\(x=\\frac{\\var{b}\\pm \\sqrt{\\simplify{{b}^2-4*{a1}*{c}}}}{\\simplify{2*{a1}}}\\)
\n\\(x=\\simplify{{b}+({b}^2-4*{a1}*{c})^0.5}/\\simplify{2*{a1}}=\\simplify{({b}+({b}^2-4*{a1}*{c})^0.5)/(2*{a1})}\\) or \\(x=\\simplify{{b}-({b}^2-4*{a1}*{c})^0.5}/\\simplify{2*{a1}}=\\simplify{({b}-({b}^2-4*{a1}*{c})^0.5)/(2*{a1})}\\)
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\n\\(x = \\) [[0]]
\nType in the lesser of the two values that satisfies the equation.
\n\\(x = \\) [[1]]
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