// Numbas version: finer_feedback_settings {"name": "Sigma notation intro 3 - subscripts ", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"variable_groups": [], "preamble": {"css": "", "js": ""}, "ungrouped_variables": ["a", "b", "f", "index"], "rulesets": {}, "variablesTest": {"condition": "", "maxRuns": 100}, "functions": {}, "tags": [], "parts": [{"variableReplacements": [], "type": "gapfill", "showCorrectAnswer": true, "variableReplacementStrategy": "originalfirst", "scripts": {}, "marks": 0, "showFeedbackIcon": true, "gaps": [{"shuffleChoices": true, "maxMarks": 0, "choices": ["
$\\var{f}_{\\var{a}}+\\var{f}_{\\var{a+1}}+\\var{f}_{\\var{a+2}}+\\ldots + \\var{f}_{\\var{b-2}}+ \\var{f}_{\\var{b-1}}+ \\var{f}_{\\var{b}}$
", "$\\var{f}_{\\var{index}}+\\var{f}_{\\var{index}}+\\var{f}_{\\var{index}}+\\ldots +\\var{f}_{\\var{index}}+\\var{f}_{\\var{index}}+\\var{f}_{\\var{index}}$
", "$\\var{a}+\\var{a+1}+\\var{a+2}+\\ldots + \\var{b-2}+ \\var{b-1}+ \\var{b}$
"], "variableReplacementStrategy": "originalfirst", "scripts": {}, "displayColumns": "1", "marks": 0, "minMarks": 0, "distractors": ["", "", ""], "type": "1_n_2", "showCorrectAnswer": true, "displayType": "radiogroup", "matrix": ["1", 0, 0], "variableReplacements": [], "showFeedbackIcon": true}], "prompt": "The expression \\[\\sum_{\\var{index}=\\var{a}}^{\\var{b}}\\var{f}_{\\var{index}}\\] is equivalent to which of the following?
\n[[0]]
"}], "advice": "Sigma notation is used to represent a sum.
\nIn this sum, we are adding up a bunch of terms that look like $\\var{f}_{\\var{index}}$ each for a different value of the index $\\var{index}$. Notice the sum starts with $\\var{index}=\\var{a}$ and ends with $\\var{index}=\\var{b}$, therefore, \\[\\sum_{\\var{index}=\\var{a}}^{\\var{b}}\\var{f}_{\\var{index}}=\\var{f}_{\\var{a}}+\\var{f}_{\\var{a+1}}+\\var{f}_{\\var{a+2}}+\\ldots + \\var{f}_{\\var{b-2}}+ \\var{f}_{\\var{b-1}}+ \\var{f}_{\\var{b}}.\\]
", "name": "Sigma notation intro 3 - subscripts ", "extensions": [], "variables": {"b": {"name": "b", "group": "Ungrouped variables", "definition": "a+random(50..79)", "templateType": "anything", "description": ""}, "index": {"name": "index", "group": "Ungrouped variables", "definition": "random(latex('i'),latex('j'),latex('k'),latex('r'),latex('s'),latex('n'),latex('m'))", "templateType": "anything", "description": ""}, "f": {"name": "f", "group": "Ungrouped variables", "definition": "random(latex('a'),latex('b'),latex('c'),latex('d'),latex('t'))", "templateType": "anything", "description": ""}, "a": {"name": "a", "group": "Ungrouped variables", "definition": "random(0..10)", "templateType": "anything", "description": ""}}, "metadata": {"licence": "Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International", "description": "Students seem to struggle with Sigma notation, this is about the easiest question possible for sigma notation.
"}, "statement": "The following question is testing whether you understand the Sigma notation used in mathematics.
", "type": "question", "contributors": [{"name": "Ben Brawn", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/605/"}], "resources": []}]}], "contributors": [{"name": "Ben Brawn", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/605/"}]}