// Numbas version: finer_feedback_settings {"name": "Differentiation: Implicit Differentiation 1", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"name": "Differentiation: Implicit Differentiation 1", "tags": [], "metadata": {"description": "

Calculating $\\frac{dy}{dx}$ from an implicit polynomial function.

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If \\[ \\simplify{{a}y-{b}x^{n}={c}y^{m}}, \\]

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find $\\tfrac{dy}{dx}$.

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As we have an equation involving the variables $x$ and $y$, but cannot rearrange the equation into the form $y=f(x)$, we need to use implicit differentiation to find $\\tfrac{dy}{dx}$. 

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Differentiating $\\simplify{{a}y-{b}x^{n}={c}y^{m}}$ with respect to $x$:

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\\[ \\simplify[all,!simplifyFractions]{{a}(d y/(d x)) - {b*n}x^{n-1} = {c*m}y^{m-1}}\\frac{dy}{dx}.\\]

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Rearranging this equation so that it is in terms of $\\tfrac{dy}{dx}$:

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{advice}

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\\\\[ \\\\begin{split} \\\\simplify[unitPower,!simplifyFractions]{{a}(d y/(d x)) -{c*m}y^{m-1}(d y/(d x))} &\\\\,= \\\\simplify{{b*n}x^{n-1}} \\\\\\\\\\\\\\\\ \\\\simplify[unitPower,!simplifyFractions]{({a}-{c*m}y^{m-1}) (d y/(d x))} &\\\\,= \\\\simplify{{b*n}x^{n-1}} \\\\\\\\\\\\\\\\ \\\\simplify[unitPower,!simplifyFractions]{(d y/(d x))} &\\\\,= \\\\simplify{{b*n}x^{n-1}/({a}-{c*m}y^{m-1})} \\\\\\\\\\\\\\\\ \\\\simplify[unitPower,!simplifyFractions]{(d y/(d x))} &\\\\,= \\\\simplify{{b*n/simp3}x^{n-1}/({a/simp3}-{c*m/simp3}y^{m-1})} .\\\\end{split} \\\\]

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\\\\[ \\\\begin{split} \\\\simplify[unitPower,!simplifyFractions]{{a}(d y/(d x)) -{c*m}y^{m-1}(d y/(d x))} &\\\\,= \\\\simplify{{b*n}x^{n-1}} \\\\\\\\\\\\\\\\ \\\\simplify[unitPower,!simplifyFractions]{({a}-{c*m}y^{m-1}) (d y/(d x))} &\\\\,= \\\\simplify{{b*n}x^{n-1}} \\\\\\\\\\\\\\\\ \\\\simplify[unitPower,!simplifyFractions]{(d y/(d x))} &\\\\,= \\\\simplify{{b*n}x^{n-1}/({a}-{c*m}y^{m-1})}. \\\\end{split} \\\\]

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$\\dfrac{dy}{dx}=$[[0]]

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