// Numbas version: finer_feedback_settings {"name": "Scalar Multiplication", "metadata": {"description": "
Exam to test students understanding of matrices multiplied by a scalar.
", "licence": "Creative Commons Attribution-NonCommercial 4.0 International"}, "duration": 0, "percentPass": 0, "showQuestionGroupNames": false, "shuffleQuestionGroups": false, "showstudentname": true, "question_groups": [{"name": "Group", "pickingStrategy": "all-ordered", "pickQuestions": 1, "questionNames": ["", ""], "variable_overrides": [[], []], "questions": [{"name": "Scalar Multiple of a Matrix", "extensions": [], "custom_part_types": [], "resources": [["question-resources/matrix_add.gif", "/srv/numbas/media/question-resources/matrix_add.gif"]], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Michael Proudman", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/269/"}, {"name": "Tamsin Smith", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/14108/"}, {"name": "Fraser Buxton", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/24224/"}], "tags": [], "metadata": {"description": "Scalar Multiplication (pre-defined sizes in answers)", "licence": "Creative Commons Attribution-NonCommercial 4.0 International"}, "statement": "Carry out the scalar multiplication on the following matrices
", "advice": "We carry out the calculation by multiplying each element by the constant:
\na)
\n$$
\\begin{aligned}
\\var{k1}A &= \\var{k1}\\var{A} \\\\
&=\\begin{pmatrix}
\\var{k1} \\times \\var{A[0][0]} & \\var{k1} \\times \\var{A[0][1]}& \\var{k1} \\times \\var{A[0][2]}\\\\
\\var{k1} \\times \\var{A[1][0]} & \\var{k1} \\times \\var{A[1][1]}& \\var{k1} \\times \\var{A[1][2]}\\\\
\\var{k1} \\times \\var{A[2][0]} & \\var{k1} \\times \\var{A[2][1]} & \\var{k1} \\times \\var{A[2][2]}\\\\
\\end{pmatrix} \\\\
&= \\var{ad1}
\\end{aligned}
$$
b)
\nUsing the same technique, we get:
\n$$
\\begin{aligned}
\\var{k2}B &= \\var{k2}\\var{B} \\\\
&= \\var{ad2}
\\end{aligned}
$$
c)
\n$$
\\begin{aligned}
\\var{k3}C &= \\var{k3}\\var{C} \\\\
&= \\var{ad3}
\\end{aligned}
$$
d)
\n$$
\\begin{aligned}
\\var{k4}D &= \\var{k4}\\var{D} \\\\
&= \\var{ad4}
\\end{aligned}
$$
e)
\n$$
\\begin{aligned}
\\var{k5}E &= \\var{k5}\\var{EE} \\\\
&= \\var{ad5}
\\end{aligned}
$$
Let:
\n$$
A=\\var{A}
$$
Calculate $\\var{k1} A$:
\n$\\var{k1}A=$ [[0]]
\n\n\n", "gaps": [{"type": "matrix", "useCustomName": false, "customName": "", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "correctAnswer": "{k1}{A}", "correctAnswerFractions": false, "numRows": "{n1}", "numColumns": "{m1}", "allowResize": false, "tolerance": 0, "markPerCell": false, "allowFractions": false, "minColumns": 1, "maxColumns": 0, "minRows": 1, "maxRows": 0, "prefilledCells": ""}], "sortAnswers": false}, {"type": "gapfill", "useCustomName": false, "customName": "", "marks": 0, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "Let:
\n$$
B=\\var{B}
$$
Calculate $\\var{k2}B$:
\n$\\var{k2}B=$ [[0]]
", "gaps": [{"type": "matrix", "useCustomName": false, "customName": "", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "correctAnswer": "{k2}{B}", "correctAnswerFractions": false, "numRows": "{n2}", "numColumns": "{m2}", "allowResize": false, "tolerance": 0, "markPerCell": false, "allowFractions": false, "minColumns": 1, "maxColumns": 0, "minRows": 1, "maxRows": 0, "prefilledCells": ""}], "sortAnswers": false}, {"type": "gapfill", "useCustomName": false, "customName": "", "marks": 0, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "Let:
\n$$
C=\\var{C}
$$
Calculate $\\var{k3}C$:
\n$\\var{k3}C=$ [[0]]
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\n$$
D=\\var{D}
$$
Calculate $\\var{k4}D$:
\n$\\var{k4}D=$ [[0]]
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\n$$
E=\\var{EE}
$$
Calculate $\\var{k5}E$:
\n$\\var{k5}E=$ [[0]]
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", "advice": "We are asked to carry out combinations of matrix operations. We combine the rules that we have used previously to determine our answer:
\na)
\nIf $A=\\var{A}$ and $B=\\var{A2}$ then:
\n$$
\\begin{aligned}
\\var{k1} A+B &= \\var{k1} \\var{A}+\\var{A2} \\\\
&=\\var{ad1}+\\var{A2} \\\\
&= \\var{ad1a}
\\end{aligned}
$$
b)
\nIf $C=\\var{B}$ and $D=\\var{B2}$ then:
\n$$
\\begin{aligned}
C - \\var{k2} D &= \\var{B} - \\var{k2} \\var{B2} \\\\
&=\\var{B}-\\var{ad2} \\\\
&= \\var{ad2a}
\\end{aligned}
$$
c)
\nIf $E=\\var{C}$ and $F=\\var{C2}$ then:
\n$$
\\begin{aligned}
\\var{k3} E - \\var{k1}F &= \\var{k3} \\var{C} - \\var{k1} \\var{C2} \\\\
&=\\var{ad3} - \\var{ad3a} \\\\
&= \\var{ad3b}
\\end{aligned}
$$
d)
\nIf $G=\\var{D}$ and $H=\\var{D2}$ then:
\n$$
\\begin{aligned}
\\var{k4} G- H &= \\var{k4} \\var{D}+\\var{D2} \\\\
&=\\var{ad4}+\\var{D2} \\\\
&= \\var{ad4a}
\\end{aligned}
$$
e)
\nIf $I=\\var{EE}$ and $J=\\var{EE2}$ then:
\n$$
\\begin{aligned}
\\var{k5} I-J &= \\var{k5} \\var{EE}-\\var{EE2} \\\\
&=\\var{ad5}-\\var{EE2} \\\\
&= \\var{ad5a}
\\end{aligned}
$$
Let:
\n$$
A=\\var{A}, B=\\var{A2}
$$
Calculate $\\var{k1}A + B$:
\n$\\var{k1} A+B=$[[0]]
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\n$$
C=\\var{B}, D=\\var{B2}
$$
Calculate $C-\\var{k2}D$:
\n$C-\\var{k2}D=$ [[0]]
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\n$$
E=\\var{C}, F=\\var{C2}
$$
Calculate $\\var{k3}E-\\var{k1}F$:
\n$\\var{k3}E-\\var{k1}F=$ [[0]]
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\n$$
G=\\var{D}, H=\\var{D2}
$$
Calculate $\\var{k4}G+H$:
\n$\\var{k4}G+H=$ [[0]]
", "gaps": [{"type": "matrix", "useCustomName": false, "customName": "", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "correctAnswer": "{k4}*{D}+{D2}", "correctAnswerFractions": false, "numRows": "{n4}", "numColumns": "{m4}", "allowResize": false, "tolerance": 0, "markPerCell": false, "allowFractions": false, "minColumns": 1, "maxColumns": 0, "minRows": 1, "maxRows": 0, "prefilledCells": ""}], "sortAnswers": false}, {"type": "gapfill", "useCustomName": false, "customName": "", "marks": 0, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "Let:
\n$$
I=\\var{EE}, J=\\var{EE2}
$$
Calculate $\\var{k5}I-J$
\n$\\var{k5}I-J=$ [[0]]
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