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Calculate the dot products of (a) two 2D vectors and (b) two 3D vectors.
", "licence": "Creative Commons Attribution 4.0 International"}, "statement": "Find the dot product (also called the scalar product) below.
", "advice": "To calculate the dot product, multiply the corresponding elements of the vectors. Hence for a 3D vector, the process is as follows:
\n$$ \\begin{bmatrix} a_1 \\\\ a_2 \\\\ a_3 \\end{bmatrix} . \\begin{bmatrix} b_1 \\\\ b_2 \\\\ b_3 \\end{bmatrix} = a_1b_1+a_2b_2+a_3b_3 .$$
\nThe answers to the questions above should be therefore calculated as follows.
\nPart A
$\\var{A}\\cdot\\var{B}=(\\var{a1}\\times\\var{B1})+(\\var{A2}\\times\\var{B2})=\\var{a1*b1+a2*b2}$
Part B
$\\var{C}\\cdot\\var{D}=(\\var{c1}\\times\\var{d1})+(\\var{c2}\\times\\var{d2})+(\\var{c3}\\times\\var{d3})=\\var{c1*d1+c2*d2+c3*d3}$
$\\var{A}\\cdot\\var{B}=$[[0]]
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", "gaps": [{"type": "numberentry", "useCustomName": false, "customName": "", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "minValue": "c1*d1+c2*d2+c3*d3", "maxValue": "c1*d1+c2*d2+c3*d3", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "displayAnswer": "", "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}], "sortAnswers": false}], "partsMode": "all", "maxMarks": 0, "objectives": [], "penalties": [], "objectiveVisibility": "always", "penaltyVisibility": "always", "contributors": [{"name": "Will Roberts", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/32402/"}], "resources": []}]}], "contributors": [{"name": "Will Roberts", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/32402/"}]}