// Numbas version: exam_results_page_options {"name": "Integration by parts 2 - cos and sin", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"advice": "

The formula for integrating by parts is

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\\[ \\int u\\frac{dv}{dx} dx = uv - \\int v \\frac{du}{dx} dx. \\]

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

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

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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} \\]

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

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The formula for integration by parts is

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\\[ \\int u\\frac{dv}{dx} dx = uv - \\int v \\frac{du}{dx} dx. \\]

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What is the most suitable choice for $u$ and $\\frac{dv}{dx}$?

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$u =\\;$[[0]]

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$\\frac{dv}{dx} =\\;$[[1]]

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Hence find $\\frac{du}{dx} =\\;$[[0]]

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$v =\\;$[[1]]

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Hence find $uv =\\;$[[0]]

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$\\int v\\frac{du}{dx}\\mathrm{d}x = \\;$[[1]]$+C$

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

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Use the results from above to find:

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$I=\\displaystyle \\int \\simplify[std]{({a}x+{b})*cos({c}x+{d})} dx = \\int u\\frac{dv}{dx} dx = uv - \\int v \\frac{du}{dx} dx = \\;$[[0]]$+C$

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Input all numbers as fractions or integers and not decimals.

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Find $\\displaystyle \\int (ax+b)\\cos(cx+d)\\; dx $

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Find the following indefinite integral.

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Input all numbers as fractions or integers and not decimals.

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Input the constant of integration as $C$.

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