// Numbas version: exam_results_page_options {"name": "Integral by hyperbolic substitution", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"variable_groups": [], "variables": {"tol": {"templateType": "anything", "group": "Ungrouped variables", "definition": "0", "description": "", "name": "tol"}, "b": {"templateType": "anything", "group": "Ungrouped variables", "definition": "random(1..8)", "description": "", "name": "b"}, "a": {"templateType": "anything", "group": "Ungrouped variables", "definition": "random(2..5)", "description": "", "name": "a"}, "valacc": {"templateType": "anything", "group": "Ungrouped variables", "definition": "(1/a)*ln((2*a+(4a^2-1)^(1/2))/(a+(a^2-1)^(1/2)))", "description": "", "name": "valacc"}, "val": {"templateType": "anything", "group": "Ungrouped variables", "definition": "precround(valacc,2)", "description": "", "name": "val"}}, "ungrouped_variables": ["a", "b", "valacc", "val", "tol"], "question_groups": [{"pickingStrategy": "all-ordered", "questions": [], "name": "", "pickQuestions": 0}], "name": "Integral by hyperbolic substitution", "functions": {}, "showQuestionGroupNames": false, "parts": [{"stepsPenalty": 0, "scripts": {}, "gaps": [{"showCorrectAnswer": true, "allowFractions": false, "scripts": {}, "type": "numberentry", "maxValue": "val+tol", "minValue": "val-tol", "correctAnswerFraction": false, "marks": 3, "showPrecisionHint": false}], "type": "gapfill", "prompt": "
$I=\\;\\;$[[0]]
\nInput your answer to $2$ decimal places.
\nShow steps has some information on the standard integral you may need. You will lose no marks in looking at this.
", "steps": [{"type": "information", "prompt": "Use the standard integral: \\[\\int \\frac{1}{\\sqrt{x^2-1}}\\;dx=\\simplify{arccosh(x)+C}\\]
", "showCorrectAnswer": true, "scripts": {}, "marks": 0}], "showCorrectAnswer": true, "marks": 0}], "statement": "Use hyperbolic functions to find the value of:
\\[I=\\int_{\\var{b}}^{\\var{2*b}} \\left(\\frac{1}{\\sqrt{\\simplify[std]{{a^2}x^2-{b^2}}}}\\right)\\;dx\\]
30/06/2012:
\nAdded, edited tags
\nSlight change to prompt.
\nCould include standard integral in Show steps (once Show steps is available)
\n19/07/2012:
\nAdded description.
\nChanged Advice on the standard integral - so that it makes sense!
\nAdded Show steps information on the standard integral.
\nChecked calculation.
\nSet new tolerance variable tol=0 for the numeric input.
\n23/07/2012:
\n \nAdded tags.
\n \nSolution always requires arccosh(x) and not arcsinh(x) or arctanh(x). Is this on purpose?
\n\n
\n
Question appears to be working correctly.
\n\n
", "licence": "Creative Commons Attribution 4.0 International", "description": "
Find (hyperbolic substitution):
$\\displaystyle \\int_{b}^{2b} \\left(\\frac{1}{\\sqrt{a^2x^2-b^2}}\\right)\\;dx$
This is the standard integral we use: \\[\\int \\frac{1}{\\sqrt{x^2-1}}\\;dx=\\simplify{arccosh(x)+C}\\]
\nFor this example if we make the substitution $\\displaystyle{x = \\simplify[std]{{b}v/{a}}}$ in our integral then we get:
\n\\[\\begin{eqnarray*} I &=&\\frac{1}{\\var{a}}\\int_{\\var{a}}^{\\var{2*a}}\\frac{1}{\\sqrt{v^2-1}}\\;dv\\\\ &=&\\frac{1}{\\var{a}}\\left[\\simplify{arccosh(v)}\\right]_{\\var{a}}^{\\var{2*a}}\\\\ &=&\\var{val} \\end{eqnarray*} \\] to 2 decimal places.
", "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/"}]}