// Numbas version: finer_feedback_settings {"name": "Harry's copy of Differentiation: Product rule", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"question_groups": [{"pickQuestions": 0, "name": "", "pickingStrategy": "all-ordered", "questions": []}], "variablesTest": {"maxRuns": 100, "condition": ""}, "name": "Harry's copy of Differentiation: Product rule", "parts": [{"type": "gapfill", "stepsPenalty": 0, "marks": 0, "prompt": "\n\t\t\t

$\\simplify[std]{f(x) = x ^ {m} * cos({a} * x+{b})}$

\n\t\t\t

$\\displaystyle \\frac{df}{dx}=\\;$[[0]]

\n\t\t\t

Clicking on Show steps gives you more information, you will not lose any marks by doing so.

\n\t\t\t", "gaps": [{"showpreview": true, "expectedvariablenames": [], "answersimplification": "std", "checkingaccuracy": 0.001, "vsetrangepoints": 5, "showCorrectAnswer": true, "type": "jme", "marks": 3, "checkingtype": "absdiff", "answer": "{m}x ^ {m-1} * cos({a} * x+{b})-{a}x^{m} * sin({a} * x+{b})", "vsetrange": [0, 1], "checkvariablenames": false, "scripts": {}}], "steps": [{"prompt": "

The product rule says that if $u$ and $v$ are functions of $x$ then
\\[\\simplify[std]{Diff(u * v,x,1) = u * Diff(v,x,1) + v * Diff(u,x,1)}\\]

", "type": "information", "showCorrectAnswer": true, "marks": 0, "scripts": {}}], "showCorrectAnswer": true, "scripts": {}}], "rulesets": {"std": ["all", "!collectNumbers", "fractionNumbers"], "surdf": [{"result": "(sqrt(b)*a)/b", "pattern": "a/sqrt(b)"}]}, "tags": ["calculus", "Calculus", "checked2015", "derivative of a product", "differentiating a product", "differentiating trigonometric functions", "differentiation", "MAS1601", "mas1601", "product rule", "Steps", "steps", "trigonometric functions"], "ungrouped_variables": ["a", "s1", "b", "m"], "variable_groups": [], "statement": "

Differentiate the following function $f(x)$ using the product rule.

", "functions": {}, "type": "question", "showQuestionGroupNames": false, "metadata": {"notes": "\n\t\t

31/07/2012:

\n\t\t

Added tags.

\n\t\t

Added description.

\n\t\t

Steps problem to be addressed. Now resolved.

\n\t\t

Checked calculation.OK.

\n\t\t

Improved prompt display.

\n\t\t

Clicking on Show steps does not lose any marks.

\n\t\t", "licence": "Creative Commons Attribution 4.0 International", "description": "

Differentiate $x^m\\cos(ax+b)$

"}, "variables": {"s1": {"group": "Ungrouped variables", "definition": "random(1,-1)", "name": "s1", "templateType": "anything", "description": ""}, "b": {"group": "Ungrouped variables", "definition": "s1*random(1..9)", "name": "b", "templateType": "anything", "description": ""}, "m": {"group": "Ungrouped variables", "definition": "random(2..9)", "name": "m", "templateType": "anything", "description": ""}, "a": {"group": "Ungrouped variables", "definition": "random(2..9)", "name": "a", "templateType": "anything", "description": ""}}, "preamble": {"js": "", "css": ""}, "advice": "\n\t \n\t \n\t

The product rule says that if $u$ and $v$ are functions of $x$ then
\\[\\simplify[std]{Diff(u * v,x,1) = u * Diff(v,x,1) + v * Diff(u,x,1)}\\]

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

For this example:

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

\\[\\simplify[std]{u = x ^ {m}}\\Rightarrow \\simplify[std]{Diff(u,x,1) = {m}x ^ {m -1}}\\]

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

\\[\\simplify[std]{v = cos({a} * x+{b})} \\Rightarrow \\simplify[std]{Diff(v,x,1) = -{a} * sin({a} * x+{b})}\\]

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

Hence on substituting into the product rule above we get:

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

\\[\\simplify[std]{Diff(f,x,1) = {m}x ^ {m-1} * cos({a} * x+{b})-{a}x^{m} * sin({a} * x+{b})}\\]

\n\t \n\t \n\t", "contributors": [{"name": "Harry Flynn", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/976/"}]}]}], "contributors": [{"name": "Harry Flynn", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/976/"}]}