// Numbas version: finer_feedback_settings {"name": "Double integral, ", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"variable_groups": [], "variables": {"ans": {"templateType": "anything", "group": "Ungrouped variables", "definition": "precround(upper-lower,3)", "description": "", "name": "ans"}, "a": {"templateType": "anything", "group": "Ungrouped variables", "definition": "random(1..9)", "description": "", "name": "a"}, "m": {"templateType": "anything", "group": "Ungrouped variables", "definition": "random(2..5)", "description": "", "name": "m"}, "fun": {"templateType": "anything", "group": "Ungrouped variables", "definition": "switch(t=1,'$\\\\sin(x^{\\\\var{m}}+\\\\var{a})$',t=2,'$\\\\cos(x^{\\\\var{m}}+\\\\var{a})$','$\\\\exp(x^{\\\\var{m}}+\\\\var{a})$')", "description": "", "name": "fun"}, "t": {"templateType": "anything", "group": "Ungrouped variables", "definition": "random(1..3)", "description": "", "name": "t"}, "upper": {"templateType": "anything", "group": "Ungrouped variables", "definition": "switch(t=1,-cos(1+a),t=2,sin(1+a),exp(1+a))", "description": "", "name": "upper"}, "lower": {"templateType": "anything", "group": "Ungrouped variables", "definition": "switch(t=1,-cos(a),t=2,sin(a),exp(a))", "description": "", "name": "lower"}}, "ungrouped_variables": ["a", "upper", "lower", "m", "t", "ans", "fun"], "question_groups": [{"pickingStrategy": "all-ordered", "questions": [], "name": "", "pickQuestions": 0}], "name": "Double integral, ", "functions": {}, "showQuestionGroupNames": false, "parts": [{"scripts": {}, "gaps": [{"showCorrectAnswer": true, "allowFractions": false, "scripts": {}, "type": "numberentry", "maxValue": "ans+0.001", "minValue": "ans-0.001", "correctAnswerFraction": false, "marks": 1, "showPrecisionHint": false}], "type": "gapfill", "prompt": "

$\\displaystyle I=\\int_0^1\\;dx\\;\\int_0^{\\simplify[all]{x^{m-1}}}\\var{m}${fun}$dy$

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$I=\\;$[[0]]

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Input your answer to 3 decimal places.

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Evaluate the following repeated integral:

", "tags": ["checked2015", "MAS1603", "MAS2304"], "rulesets": {}, "preamble": {"css": "", "js": ""}, "type": "question", "metadata": {"notes": "

01/02/2013:

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First draft completed. 

", "licence": "Creative Commons Attribution 4.0 International", "description": "

Repeated integral of the form: $\\displaystyle I=\\int_0^1\\;dx\\;\\int_0^{x^{m-1}}mf(x^m+a)dy$

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We want to find

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$\\displaystyle I=\\int_0^1\\;dx\\;\\int_0^{\\simplify[all]{x^{m-1}}}\\var{m}${fun}$dy$

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The innermost integral gives:

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$\\displaystyle \\int_0^{\\simplify[all]{x^{m-1}}}\\var{m}${fun}$dy=\\left[\\var{m}y\\;\\right.${fun}$\\displaystyle \\left. \\right]_0^{\\simplify[all]{x^{m-1}}}=\\simplify[all]{{m}x^{m-1}}${fun}

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So we have to find  $\\displaystyle I=\\int_0^1\\simplify[all]{{m}x^{m-1}}${fun}$dx$

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Note that if we use the substitution $u=\\simplify[all]{x^{m}+{a}}$ then it is easy to find this last definite integral and we find that:

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$I=\\var{ans}$ to 3 decimal places.

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", "contributors": [{"name": "Newcastle University Mathematics and Statistics", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/697/"}]}]}], "contributors": [{"name": "Newcastle University Mathematics and Statistics", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/697/"}]}