// Numbas version: finer_feedback_settings {"name": "Hyperbolic Functions 2", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"functions": {}, "ungrouped_variables": ["a", "b", "n", "a1", "a2", "b1", "b2"], "name": "Hyperbolic Functions 2", "tags": ["Calculus", "Differentiation", "calculus", "chain rule", "cosh", "derivatives of hyperbolic functions", "differential", "differentiate", "differentiating hyperbolic functions", "differentiation", "hyperbolic functions", "product rule", "sinh", "tanh"], "preamble": {"css": "", "js": ""}, "advice": "

Here is a table of the derivatives of some of the hyperbolic functions:

\n\n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n
$f(x)$$\\displaystyle{\\frac{df}{dx}}$
$\\sinh(bx)$$b\\cosh(bx)$
$\\cosh(bx)$$b\\sinh(bx)$
$\\tanh(bx)$$\\simplify{b*sech(bx)^2}$
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a)

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$f(x)=\\simplify[std]{ x ^ {n} * sinh({a1} * x + {b1})}$

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Use the product rule to obtain:
\\[\\frac{df}{dx} = \\simplify[std]{{n} * (x ^ {(n -1)}) * sinh({a1} * x + {b1}) + {a1} * (x ^ {n}) * Cosh({a1} * x + {b1})}\\]

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b)

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$f(x)=\\tanh(\\simplify[std]{{a}x+{b}})$

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Using the table above we get:
\\[\\frac{df}{dx} = \\simplify[std]{{a}*sech({a}x+{b})^2}\\]

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c)

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$f(x)=\\ln(\\cosh(\\simplify[std]{{a2}x+{b2}}))$

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Using the chain rule we find:

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\\[\\frac{df}{dx} = \\simplify[std]{{a2} * tanh({a2} * x + {b2})}\\]

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$f(x)=\\simplify[std]{ x ^ {n} * sinh({a1} * x + {b1})}$

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

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$f(x)=\\tanh(\\simplify[std]{{a}x+{b}})$

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

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$f(x)=\\ln(\\cosh(\\simplify[std]{{a2}x+{b2}}))$

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

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Write down the derivatives of the following functions $f(x)$ .

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Note that in order to input the square of a function such as $\\sinh(x)$ you have to input it as sinh(x))^2, similarly for the other hyperbolic functions.

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29/06/2012:

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Added and edited tags.

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19/07/2012:

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Added description.

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There is also the problem of inputting functions of the form $xf(x)$ if $n=1$ or $2$ in the first question. So have reset $n$ to between $3$ and $7$. Otherwise would have to have an instruction here (perhaps depending on value of $n$).

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Checked calculation.

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23/07/2012:

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Added tags.

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Question appears to be working correctly.

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

Differentiate the following functions: $\\displaystyle x ^ n \\sinh(ax + b),\\;\\tanh(cx+d),\\;\\ln(\\cosh(px+q))$

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