// Numbas version: exam_results_page_options {"name": "mathcentre: Indefinite integration", "type": "exam", "duration": 0, "metadata": {"notes": "", "description": "

5 questions on indefinite integration. Includes integration by parts and integration by substitution.

", "licence": "Creative Commons Attribution 4.0 International"}, "allQuestions": true, "shuffleQuestions": false, "questions": [], "percentPass": 0, "timing": {"allowPause": true, "timeout": {"action": "none", "message": ""}, "timedwarning": {"action": "none", "message": ""}}, "pickQuestions": 0, "navigation": {"onleave": {"action": "none", "message": ""}, "reverse": true, "allowregen": true, "preventleave": false, "browse": true, "showfrontpage": false, "showresultspage": "never"}, "feedback": {"showtotalmark": true, "advicethreshold": 0, "showanswerstate": true, "showactualmark": true, "allowrevealanswer": true}, "showQuestionGroupNames": false, "question_groups": [{"name": "", "pickingStrategy": "all-ordered", "pickQuestions": 0, "questions": [{"name": "Indefinite integral", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Bill Foster", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/6/"}], "functions": {}, "tags": ["Calculus", "Steps", "calculus", "constant of integration", "indefinite integration", "integrals", "integrating fractional powers", "integrating powers", "integration", "standard integrals", "steps"], "advice": "\n \n \n

Using
\\[\\int \\;x^n\\;dx=\\frac{x^{n+1}}{n+1}+C\\] for any number $n \\neq -1$ we have
\\[\\begin{eqnarray*}\n \n \\simplify[std]{Int({c}*x^{m}+{d}*x ^ ({b} / {n}),x)} &=&\\simplify[std]{ ({c} / {m + 1}) * x ^ {m + 1} +{d}* x ^ ({b} / {n} + 1) / ({b} / {n} + 1) + C }\\\\\n \n &=&\\simplify[std]{ ({c} / {m + 1}) * x ^ {m + 1} + ({d*n} / {b + n}) * x ^ ({b + n} / {n}) + C}\n \n \\end{eqnarray*}\\]

\n \n \n ", "rulesets": {"std": ["all", "!collectNumbers", "fractionNumbers"], "surdf": [{"pattern": "a/sqrt(b)", "result": "(sqrt(b)*a)/b"}]}, "parts": [{"stepspenalty": 0.0, "prompt": "\n

$\\simplify[std]{f(x) = {c}x ^ {m} + {d}*x^({b}/{n})}$

\n

$\\displaystyle \\int\\;f(x)\\,dx=\\;$[[0]]

\n

Input all numbers as integers or fractions and not decimals. Remember to include the constant of integration $C$.

\n

Click on Show steps to get more information. You will not lose any marks by doing so.

\n ", "gaps": [{"notallowed": {"message": "

Input all numbers as integers or fractions and not decimals.

", "showstrings": false, "strings": ["."], "partialcredit": 0.0}, "checkingaccuracy": 0.001, "vsetrange": [1.0, 2.0], "vsetrangepoints": 5.0, "checkingtype": "absdiff", "answersimplification": "std", "marks": 3.0, "answer": "({c}/{m+1})x ^ {m+1} + ({d*n}/{b+n})*x^({n+b}/{n})+C", "type": "jme"}], "steps": [{"prompt": "

The indefinite integral of a power $x^n$ where $n\\neq -1$ is \\[\\int \\;x^n\\;dx=\\frac{x^{n+1}}{n+1}+C\\]

", "type": "information", "marks": 0.0}], "marks": 0.0, "type": "gapfill"}], "statement": "\n

Integrate the following function $f(x)$.

\n


Input the constant of integration as $C$.

\n ", "variable_groups": [], "progress": "ready", "type": "question", "variables": {"a": {"definition": "random(1..5)", "name": "a"}, "c": {"definition": "s1*random(2..9)", "name": "c"}, "b": {"definition": "random(2..9)", "name": "b"}, "d": {"definition": "random(2..9)", "name": "d"}, "s1": {"definition": "random(1,-1)", "name": "s1"}, "m": {"definition": "random(3..9)", "name": "m"}, "n": {"definition": "a*b+r", "name": "n"}, "r": {"definition": "random(1..b-1)", "name": "r"}}, "metadata": {"notes": "\n \t\t

2/08/2012:

\n \t\t

Added tags.

\n \t\t

Added description.

\n \t\t

Checked calculation. OK.

\n \t\t

Added decimal point to forbidden strings along with message to user re input of numbers.

\n \t\t

Message about Show steps included. Also another message about including the constant of integration.

\n \t\t

Changed checking range from 0 to 1 to 1 to 2.

\n \t\t

Improved display.

\n \t\t", "description": "

Find $\\displaystyle \\int ax ^ m+ bx^{c/n}\\;dx$.

", "licence": "Creative Commons Attribution 4.0 International"}, "showQuestionGroupNames": false, "question_groups": [{"name": "", "pickingStrategy": "all-ordered", "pickQuestions": 0, "questions": []}]}, {"name": "Indefinite integral", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Bill Foster", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/6/"}], "functions": {}, "tags": ["Calculus", "Steps", "calculus", "constant of integration", "exponential function", "indefinite integration", "integrals", "integrating powers", "integration", "integration of exponential function", "integration of powers", "integration of trigonometric functions", "standard integrals", "steps", "trigonometric functions"], "advice": "\n

Note that \\[\\begin{eqnarray*} &\\int& \\;x^n\\;dx&=&\\frac{x^{n+1}}{n+1}+C,\\;\\;n \\neq -1\\\\ &\\int& \\;\\sin(ax)\\;dx &=& -\\frac{1}{a}\\cos(ax)+C\\\\ &\\int& \\;e^{ax}\\;dx &=& \\frac{1}{a}e^{ax}+C\\\\ \\end{eqnarray*}\\]

\n

Splitting the integral into three parts and using the above information we have:
\\[\\begin{eqnarray*}\\simplify[std]{Int({b} * e ^ ({a}*x) + {b1} * Sin({a1}*x) + {a2} * x ^ {c3},x)}&=&\\simplify[std]{Int({b} * e ^ ({a}*x),x)+Int({b1} * Sin({a1}*x),x)+Int({a2} * x ^ {c3},x) }\\\\ &=&\\simplify[std]{({b}/{a}) * (e ^({a}*x)) + (({(-b1)}/{a1}) * Cos({a1}*x)) + ({a2}/{c3+1}) * (x ^ {(c3 + 1)})+C} \\end{eqnarray*}\\]

\n ", "rulesets": {"std": ["all", "!collectNumbers", "fractionNumbers"], "surdf": [{"pattern": "a/sqrt(b)", "result": "(sqrt(b)*a)/b"}]}, "parts": [{"stepspenalty": 0.0, "prompt": "\n

$\\simplify[std]{f(x) = {b} * e ^ ({a}*x) + {b1} * Sin({a1}*x) + {a2} * x ^ {c3}}$

\n

$\\displaystyle \\int\\;f(x)\\,dx=\\;$[[0]]

\n

Input all numbers as integers or fractions and not decimals. Remember to include the constant of integration $C$.

\n

Click on Show steps to get more information. You will not lose any marks by doing so.

\n ", "gaps": [{"notallowed": {"message": "

Input all numbers as integers or fractions and not decimals.

", "showstrings": false, "strings": ["."], "partialcredit": 0.0}, "checkingaccuracy": 0.001, "vsetrange": [1.0, 2.0], "vsetrangepoints": 5.0, "checkingtype": "absdiff", "answersimplification": "std", "marks": 3.0, "answer": "({b}/{a}) * (e ^({a}*x)) + (({(-b1)}/{a1}) * Cos({a1}*x)) + ({a2}/{c3+1}) * (x ^ {(c3 + 1)})+C", "type": "jme"}], "steps": [{"prompt": "

Note that \\[\\begin{eqnarray*} &\\int& \\;x^n\\;dx&=&\\frac{x^{n+1}}{n+1}+C,\\;\\;n \\neq -1\\\\ &\\int& \\;\\sin(ax)\\;dx &=& -\\frac{1}{a}\\cos(ax)+C\\\\ &\\int& \\;e^{ax}\\;dx &=& \\frac{1}{a}e^{ax}+C\\\\ \\end{eqnarray*}\\]

", "type": "information", "marks": 0.0}], "marks": 0.0, "type": "gapfill"}], "statement": "\n

Integrate the following function $f(x)$.

\n

 
Input the constant of integration as $C$.

\n ", "variable_groups": [], "progress": "ready", "type": "question", "variables": {"a": {"definition": "s1*random(2..5)", "name": "a"}, "b": {"definition": "s2*random(2..9)", "name": "b"}, "s3": {"definition": "random(1,-1)", "name": "s3"}, "s2": {"definition": "random(1,-1)", "name": "s2"}, "s1": {"definition": "random(1,-1)", "name": "s1"}, "s5": {"definition": "random(1,-1)", "name": "s5"}, "s4": {"definition": "random(1,-1)", "name": "s4"}, "a1": {"definition": "random(2..5)", "name": "a1"}, "a2": {"definition": "s4*random(3..9)", "name": "a2"}, "b1": {"definition": "s3*random(2..9)", "name": "b1"}, "c3": {"definition": "s5*random(2..8)", "name": "c3"}}, "metadata": {"notes": "\n \t\t

2/08/2012:

\n \t\t

Added tags.

\n \t\t

Added description.

\n \t\t

Corrected mistake in formula for integrating $\\sin(ax)$ in Steps and Advice.

\n \t\t

Checked calculation. OK.

\n \t\t

Added decimal point to forbidden strings along with message to user re input of numbers.

\n \t\t

Message about Show steps included. Also another message about including the constant of integration.

\n \t\t

Changed checking range from 0 to 1 to 1 to 2 as we can have negative powers of $x$.

\n \t\t

Improved display of Steps by aligning integral signs.

\n \t\t", "description": "

Find $\\displaystyle \\int ae ^ {bx}+ c\\sin(dx) + px ^ {q}\\;dx$.

", "licence": "Creative Commons Attribution 4.0 International"}, "showQuestionGroupNames": false, "question_groups": [{"name": "", "pickingStrategy": "all-ordered", "pickQuestions": 0, "questions": []}]}, {"name": "Indefinite integral", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Bill Foster", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/6/"}], "functions": {}, "tags": ["Calculus", "Steps", "calculus", "constant of integration", "indefinite integration", "integrals", "integration", "integration by substitution", "standard integrals", "steps", "substitution"], "advice": "\n

Let $y = \\simplify[std]{{a}*x+{d}}$. Then,
\\[\\simplify[std]{{b}/(({a}*x+{d})^{n})} = \\simplify[std]{{b}/(y^{n})}.\\]

\n

Now,
\\[\\int \\simplify[std]{{b}/({a}*x+{d})^{n}} dx = \\int \\simplify[std]{{b}/(y^{n})} \\frac{dx}{dy} dy.\\]

\n

Rearrange $y = \\simplify[std]{{a}x+{d}}$ to get $\\displaystyle x = \\simplify[std]{(y-{b})/{a}}$, and hence $\\displaystyle\\frac{dx}{dy} = \\frac{1}{\\var{a}}$.

\n

$\\displaystyle \\int \\frac{1}{y^n} dx = -\\frac{1}{(n-1)y^{n-1}} + C$ is a standard integral, so we can now calculate the desired integral:

\n

\\[\\int \\simplify[std]{{b}/(y^{n})} \\frac{dx}{dy} dy = \\simplify[std]{{b}/({n-1}*y^{n-1})} \\cdot \\frac{1}{\\var{a}} + C = \\simplify[std]{(-{b})/({a*(n-1)}*({a}*x+{d})^{n-1}) + C}.\\]

\n ", "rulesets": {"std": ["all", "!collectNumbers", "fractionNumbers", "!noLeadingMinus"], "surdf": [{"pattern": "a/sqrt(b)", "result": "(sqrt(b)*a)/b"}]}, "parts": [{"stepspenalty": 1.0, "prompt": "\n

$\\displaystyle \\int \\simplify[std]{{b}/(({a}*x+{d})^{n})} dx= \\phantom{{}}$[[0]]

\n

Input all numbers as integers or fractions and not decimals. Remember to include the constant of integration $C$.

\n

Click on Show steps to get help. You will lose 1 mark by doing so.

\n ", "gaps": [{"notallowed": {"message": "

Input all numbers as integers or fractions and not decimals.

", "showstrings": false, "strings": ["."], "partialcredit": 0.0}, "checkingaccuracy": 0.0001, "vsetrange": [0.0, 1.0], "vsetrangepoints": 5.0, "checkingtype": "reldiff", "answersimplification": "std", "marks": 3.0, "answer": "(-{b})/({a*(n-1)}*({a}*x+{d})^{n-1}) + C", "type": "jme"}], "steps": [{"prompt": "

 \\[\\int (ax+b)^n \\;dx = \\frac{1}{a(n+1)}(ax+b)^{n+1}+C\\]

", "type": "information", "marks": 0.0}], "marks": 0.0, "type": "gapfill"}], "statement": "\n \n \n

Find the following indefinite integral.

\n \n \n \n

Input the constant of integration as $C$.

\n \n \n ", "variable_groups": [], "progress": "ready", "type": "question", "variables": {"a": {"definition": "random(2..9)", "name": "a"}, "b": {"definition": "random(2..5)", "name": "b"}, "d": {"definition": "random(1..9)", "name": "d"}, "n": {"definition": "random(3..5)", "name": "n"}}, "metadata": {"notes": "\n \t\t

2/08/2012:

\n \t\t

Added tags.

\n \t\t

Added description.

\n \t\t

Added decimal point to forbidden strings along with message to user re input of numbers.

\n \t\t

Added a Step and message about Show steps included - losing 1 mark if used as it gives the formula for finding the integral. Increased marks to 3 for the question, so that can cope with losing a mark for using Show steps.

\n \t\t

Changed accuracy setting to relative difference of 0.00001 as we have negative powers.

\n \t\t

Checked calculation. OK.

\n \t\t

Added message in prompt  about including the constant of integration.

\n \t\t

Noted issue with steps-answer order and the messages/marks generated.

\n \t\t

Changed numerator to the range 2..5.

\n \t\t

Improved display in Advice.

\n \t\t

 

\n \t\t", "description": "

Find $\\displaystyle \\int \\frac{a}{(bx+c)^n}\\;dx$

", "licence": "Creative Commons Attribution 4.0 International"}, "showQuestionGroupNames": false, "question_groups": [{"name": "", "pickingStrategy": "all-ordered", "pickQuestions": 0, "questions": []}]}, {"name": "Indefinite integral", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Bill Foster", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/6/"}], "functions": {}, "tags": ["Calculus", "Steps", "calculus", "constant of integration", "indefinite integration", "integration", "integration by substitution", "steps", "substitution"], "advice": "\n

Let $y = \\simplify[std]{{a}*x+{d}}$.

\n

Then $\\displaystyle x=\\frac{1}{\\var{a}}\\simplify[std]{(y-{d})}$ and so we have the numerator $\\simplify[std]{{b}*x+{c}}$ becomes in terms of $y$:

\n

$\\displaystyle \\simplify[std]{{b}*x+{c} = {b}*1/{a}*(y-{d})+{c}= {m}y+{r}}$ and so

\n

\\[\\displaystyle \\simplify[std]{({b}*x+{c})/(({a}*x+{d})^{n})} = \\simplify[std]{({m}*y+{r})/(y^{n})={m}/y^{n-1}+{r}/y^{n}}\\]

\n

Now,
\\[\\int \\simplify[std]{({b}x+{c})/({a}*x+{d})^{n}} dx = \\int \\left(\\simplify[std]{{m}/y^{n-1}+{r}/y^{n}} \\right)\\frac{dx}{dy} dy \\]

\n

Since $\\displaystyle x = \\simplify[std]{(y-{d})/{a}}$ then $\\displaystyle \\frac{dx}{dy} = \\frac{1}{\\var{a}}$.

\n

We can now calculate the desired integral:

\n

\\[ \\begin{eqnarray*} \\int \\left(\\simplify[std]{{m}/y^{n-1}+{r}/y^{n}}\\right) \\frac{dx}{dy} dy &=&\\frac{1}{\\var{a}}\\left(\\int \\simplify[std]{{m}/y^{n-1}}\\;dy+\\int \\simplify[std]{{r}/y^{n}}\\;dy \\right)\\\\ &=&\\frac{1}{\\var{a}}\\left(\\simplify[std]{{-m}/({n-2}*y^{n-2})+ {-r}/({n-1}*y^{n-1})}\\right) + C \\\\ &=& \\simplify[std]{(-{m})/({a*(n-2)}*({a}*x+{d})^{n-2})+(-{r})/({a*(n-1)}*({a}*x+{d})^{n-1}) + C}\\\\ &=&\\simplify[std]{1/({a}x+{d})^{n-1}*(({-m}/{a*(n-2)})*({a}x+{d})-{r}/({a*(n-1)}))}\\\\ &=&\\simplify[std]{1/({a}x+{d})^{n-1}*(({-m}/{(n-2)})*x+{-m*d*(n-1)-r*(n-2)}/{(n-2)*(n-1)*a})} \\end{eqnarray*} \\]
Hence \\[g(x)=\\simplify[std]{({-m}/{(n-2)})*x+{-m*d*(n-1)-r*(n-2)}/{(n-2)*(n-1)*a}}\\]

\n ", "rulesets": {"std": ["all", "!collectNumbers", "fractionNumbers", "!noLeadingMinus"]}, "parts": [{"stepspenalty": 1.0, "prompt": "\n

$I=\\displaystyle \\int \\simplify[std]{({b}*x+{c})/(({a}*x+{d})^{n})} dx$

\n

You are given that \\[I=\\simplify[std]{g(x)*({a}x+{d})^{1-n}}+C\\] for a polynomial $g(x)$. You have to find $g(x)$.

\n

$g(x)=\\;$[[0]]

\n

Remember to input all numbers as integers or fractions.

\n

Click on Show steps to get help if you need it. You will lose 1 mark by doing so.

\n ", "gaps": [{"notallowed": {"message": "

Do not input numbers as decimals, only as integers without the decimal point, or fractions

", "showstrings": false, "strings": ["."], "partialcredit": 0.0}, "checkingaccuracy": 0.001, "vsetrange": [0.0, 1.0], "vsetrangepoints": 5.0, "checkingtype": "absdiff", "answersimplification": "std", "marks": 3.0, "answer": "({-m}/{n-2})*x-{m*d*(n-1)+r*(n-2)}/{(n-2)*(n-1)*a}", "type": "jme"}], "steps": [{"prompt": "

One way to do this is by substitution, for example $y = \\simplify[std]{{a}*x+{d}}$.

", "type": "information", "marks": 0.0}], "marks": 0.0, "type": "gapfill"}], "statement": "\n

Find the following indefinite integral.

\n

Input all numbers as integers or fractions, not as decimals.

\n

Input the constant of integration as $C$.

\n ", "variable_groups": [], "progress": "ready", "type": "question", "variables": {"a": {"definition": "random(2..5)", "name": "a"}, "c": {"definition": "m*d+r", "name": "c"}, "b": {"definition": "m*a", "name": "b"}, "d": {"definition": "random(1..5)", "name": "d"}, "s2": {"definition": "random(1,-1)", "name": "s2"}, "s1": {"definition": "random(1,-1)", "name": "s1"}, "m": {"definition": "s1*random(1..4)", "name": "m"}, "n": {"definition": "random(3..5)", "name": "n"}, "r": {"definition": "s2*random(1..5)", "name": "r"}}, "metadata": {"notes": "\n \t\t

2/08/2012:

\n \t\t

Added tags.

\n \t\t

Added description.

\n \t\t

Added a Step and message about Show steps included - losing 1 mark if used as it gives the formula for finding the integral. Increased marks to 3 for the question, so that can cope with losing a mark for using Show steps.

\n \t\t

Checked calculation. OK.

\n \t\t

Improved display in Advice.

\n \t\t", "description": "

Find the polynomial $g(x)$ such that $\\displaystyle \\int \\frac{ax+b}{(cx+d)^{n}} dx=\\frac{g(x)}{(cx+d)^{n-1}}+C$.

", "licence": "Creative Commons Attribution 4.0 International"}, "showQuestionGroupNames": false, "question_groups": [{"name": "", "pickingStrategy": "all-ordered", "pickQuestions": 0, "questions": []}]}, {"name": "Leicester: Integration 3", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Bill Foster", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/6/"}], "functions": {}, "tags": ["Calculus", "Steps", "calculus", "constant of integration", "indefinite integration", "integrals", "integrating", "integrating trigonometric functions", "integration by parts", "steps", "twice"], "advice": "\n

a)

\n

The formula for integrating by parts is
\\[ \\int u\\frac{dv}{dx} dx = uv - \\int v \\frac{du}{dx} dx. \\]

\n

We choose $u = \\simplify[std]{({a}x+{b})}$ and $\\displaystyle \\frac{dv}{dx} = \\simplify[std]{cos({c}*x+{d})}$.

\n

So $\\displaystyle \\frac{du}{dx} = \\simplify[std]{{a}}$ and $\\displaystyle v = \\simplify[std]{(1/{c})*sin({c}*x+{d})}$.

\n

Hence,
\\[ \\begin{eqnarray} \\int \\simplify[std]{({a}*x+{b})*cos({c}*x+{d})} dx &=& uv - \\int v \\frac{du}{dx} dx \\\\ &=& \\simplify[std]{(({a}*x+{b})/{c})*sin({c}*x+{d}) - ({a}/{c})*Int(sin({c}*x+{d}),x)} \\\\ &=& \\simplify[std]{(({a}x+{b})/{c})*sin({c}*x+{d}) +({a}/{c^2})*cos({c}*x+{d}) + C} \\end{eqnarray} \\]

\n

b)

\n

For this part we choose $u = \\simplify[std]{({a}x+{b})^2}$ and $\\displaystyle \\frac{dv}{dx} = \\simplify[std]{sin({c}*x+{d})}$.

\n

So $\\displaystyle \\frac{du}{dx}=\\simplify[std]{{2*a}*({a}*(x)+{b})}$ and $\\displaystyle v = \\simplify[std]{-(1/{c})*cos({c}*x+{d})}$.

\n

Hence,
\\[ \\begin{eqnarray*}I= \\int \\simplify[std]{({a}*x+{b})^2*e^({c}*x)} dx &=& uv - \\int v \\frac{du}{dx} dx \\\\ &=& \\simplify[std]{({-1}/{c})*({a}x+{b})^2*cos({c}*x+{d}) + (1/{c})*Int({2*a}*({a}x+{b})*cos({c}*x+{d}),x)} \\\\ &=& \\simplify[std]{({-1}/{c})*({a}x+{b})^2*cos({c}*x+{d}) +({2*a}/{c})*Int(({a}x+{b})*cos({c}*x+{d}),x)}\\dots (*) \\end{eqnarray*}\\]

\n

But in Part a we have aready worked out $\\displaystyle \\simplify[std]{Int(({a}x+{b})*cos({c}*x+{d}),x)=(({a}x+{b})/{c})*sin({c}*x+{d}) +({a}/{c^2})*cos({c}*x+{d})}$ 

\n

So on substituting this in equation (*) we find:
\\[ \\begin{eqnarray*}I&=& \\simplify[std]{({-1}/{c})*({a}x+{b})^2*cos({c}*x+{d}) +({2*a}/{c})*((({a}x+{b})/{c})*sin({c}*x+{d}) +({a}/{c^2})*cos({c}*x+{d}))+C}\\\\ &=& \\simplify[std]{-(({a}*x+{b})^2/{c})*cos({c}*x+{d})+(({2*a}({a}x+{b}))/{c^2})*sin({c}*x+{d})+({2*a^2}/{c^3})*cos({c}*x+{d})+C} \\end{eqnarray*}\\]

\n

c)

\n

Let $\\displaystyle A= \\simplify[std]{int(exp({c1}x)*( {u}*sin({d1}x)+{1-u}*cos({d1}x)),x)} $. We solve this using two integration by parts, and we choose $u = \\simplify[std]{ {u}*sin({d1}x)+{1-u}*cos({d1}x)}$ in both. 

\n

\\[\\begin{eqnarray*} A&=&\\simplify[std]{ 1/{c1}exp({c1}x)*( {u}*sin({d1}x)+{1-u}*cos({d1}x))+{((-1)^u)*d1}/{c1}int(exp({c1}x) *({u}*cos({d1}x)+{(1-u)}*sin({d1}x)),x)}\\\\&=&\\simplify[std]{1/{c1}exp({c1}x)*( {u}*sin({d1}x)+{1-u}*cos({d1}x))+{((-1)^u)*d1}/{c1}*(1/{c1}exp({c1}x)*( {u}*cos({d1}x)+{1-u}*sin({d1}x))+{(-1)^(u+1)*d1}/{c1}int(exp({c1}x)*( {u}*sin({d1}x)+{1-u}*cos({d1}x)),x) )}\\\\&=&\\simplify[std]{1/{c1}exp({c1}x)*( {u}*sin({d1}x)+{1-u}*cos({d1}x))+{((-1)^u)*d1}/{c1}*(1/{c1}exp({c1}x)*( {u}*cos({d1}x)+{1-u}*sin({d1}x))+{(-1)^(u+1)*d1}/{c1}A )}\\end{eqnarray*}\\]

\n

Note that after integrating by parts twice, we have the integral $A$ on both sides of this equation.

\n

Rearranging we have: \\[A = \\simplify[std]{e^({c1}x)/{c1^2+d1^2}*(({u*(c1-d1)+d1})*sin({d1}x)+({u*(-c1-d1)+c1})*cos({d1}x))+C}\\]

\n ", "rulesets": {"std": ["all", "fractionNumbers", "!noLeadingMinus", "!collectNumbers"]}, "parts": [{"stepspenalty": 1.0, "prompt": "\n

$I=\\displaystyle \\int \\simplify[std]{({a}x+{b})*cos({c}x+{d})} dx $

\n

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

\n

Input all numbers as fractions or integers and not decimals.

\n

You can get help by clicking on Show steps. You will lose 1 mark if you do.

\n ", "gaps": [{"notallowed": {"message": "

Do not input numbers as decimals, only as integers without the decimal point, or fractions

", "showstrings": false, "strings": ["."], "partialcredit": 0.0}, "checkingaccuracy": 0.001, "vsetrange": [0.0, 1.0], "vsetrangepoints": 5.0, "checkingtype": "absdiff", "answersimplification": "std", "marks": 2.0, "answer": "({a}*x+{b})/{c}*sin({c}*x+{d})+{a}/{c^2}*cos({c}*x+{d})+C", "type": "jme"}], "steps": [{"prompt": "\n \n \n

The formula for integrating by parts is
\\[ \\int u\\frac{dv}{dx} dx = uv - \\int v \\frac{du}{dx} dx. \\]

\n \n \n \n \n ", "type": "information", "marks": 0.0}], "marks": 0.0, "type": "gapfill"}, {"prompt": "\n

Use the result from the first part to find:

\n

$\\displaystyle I=\\int \\simplify[std]{({a}x+{b})^2*sin({c}*x+{d})} dx $

\n

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

\n

Input all numbers as fractions or integers and not decimals.

\n \n \n ", "gaps": [{"notallowed": {"message": "

Do not input numbers as decimals, only as integers without the decimal point, or fractions

", "showstrings": false, "strings": ["."], "partialcredit": 0.0}, "checkingaccuracy": 0.001, "vsetrange": [0.0, 1.0], "vsetrangepoints": 5.0, "checkingtype": "absdiff", "answersimplification": "std", "marks": 4.0, "answer": "(-({a}*x+{b})^2/{c})*cos({c}*x+{d})+(({2*a}({a}x+{b}))/{c^2})*sin({c}*x+{d})+({2*a^2}/{c^3})*cos({c}*x+{d})+C", "type": "jme"}], "type": "gapfill", "marks": 0.0}, {"notallowed": {"message": "

Input all numbers as fractions or integers and not decimals.

", "showstrings": false, "strings": ["."], "partialcredit": 0.0}, "prompt": "\n

Find $\\displaystyle \\simplify[std]{int(exp({c1}x)*({u}*sin({d1}x)+{1-u}*cos({d1}x)),x)}$.

\n

Input all numbers as fractions or integers and not decimals.

\n

Input your answer here:

\n ", "checkingaccuracy": 0.001, "vsetrange": [0.0, 1.0], "vsetrangepoints": 5.0, "checkingtype": "absdiff", "answersimplification": "std", "marks": 3.0, "answer": "e^({c1}x)/{c1^2+d1^2}*(({u*(c1-d1)+d1})*sin({d1}x)+({u*(-c1-d1)+c1})*cos({d1}x))+C", "type": "jme"}], "statement": "\n

Find the following indefinite integrals using integration by parts.

\n

Input all numbers as fractions or integers and not decimals.

\n

Input the constant of integration as $C$.

\n ", "variable_groups": [], "progress": "ready", "type": "question", "variables": {"a": {"definition": "random(2..5)", "name": "a"}, "c": {"definition": "random(2..5)", "name": "c"}, "b": {"definition": "s1*random(1..9)", "name": "b"}, "d": {"definition": "s2*random(1..9)", "name": "d"}, "s2": {"definition": "random(1,-1)", "name": "s2"}, "s1": {"definition": "random(1,-1)", "name": "s1"}, "u": {"definition": "random(0,1)", "name": "u"}, "c1": {"definition": "random(2..6)", "name": "c1"}, "d1": {"definition": "random(2..6)", "name": "d1"}}, "metadata": {"notes": "\n \t\t \t\t \t\t

3/08/2012:

\n \t\t \t\t \t\t

Added tags.

\n \t\t \t\t \t\t

Added description.

\n \t\t \t\t \t\t

Got rid of redundant ruleset, added !noLeadingMinus to std ruleset as we need to keep the standard order for integrating by parts.

\n \t\t \t\t \t\t

Checked calculation. OK.

\n \t\t \t\t \t\t

Penalised use of steps in first part, 1 mark. Added message to that effect in first part.

\n \t\t \t\t \t\t

Added message about not inputting decimals in appropriate places.

\n \t\t \t\t \t\t

Changed marks reflecting the use of steps and degree of difficulty in second part.

\n \t\t \t\t \t\t

Improved Advice display.

\n \t\t \t\t \n \t\t \n \t\t", "description": "\n \t\t

Find $\\displaystyle \\int (ax+b)\\cos(cx+d)\\; dx $ and hence find $\\displaystyle \\int (ax+b)^2\\sin(cx+d)\\; dx $ 

\n \t\t

Also two other questions on integrating by parts.

\n \t\t", "licence": "Creative Commons Attribution 4.0 International"}, "showQuestionGroupNames": false, "question_groups": [{"name": "", "pickingStrategy": "all-ordered", "pickQuestions": 0, "questions": []}]}]}], "contributors": [{"name": "Newcastle University Mathematics and Statistics", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/697/"}], "extensions": [], "custom_part_types": [], "resources": []}