Calculus 2 : Derivative Review

Study concepts, example questions & explanations for Calculus 2

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Example Questions

Example Question #1521 : Calculus Ii

\(\displaystyle \begin{align*}&\text{Calculate the derivative of the function}\\&17cos(16sin(6x))\end{align*}\)

Possible Answers:

\(\displaystyle -17sin(16sin(6x))\)

\(\displaystyle 96cos(6x)\)

\(\displaystyle -1632sin(16sin(6x))cos(6x)\)

\(\displaystyle 17cos(96cos(6x))\)

Correct answer:

\(\displaystyle -1632sin(16sin(6x))cos(6x)\)

Explanation:

\(\displaystyle \begin{align*}&\text{Our function, }17cos(16sin(6x))\text{, is one function nested within another.}\\&\text{Note the }16sin(6x)\text{ inside of the }17cos()\\&\text{We'll wish to use the chain rule:}\\&(f\circ g )'=(f'\circ g )\cdot g'\\&\text{Along with the following:}\\&d[sin(u)]=cos(u)du\\&d[cos(u)]=-sin(u)du\\&u=16sin(6x)\\&du=96cos(6x)\\&f'(x)=(96cos(6x))(-17sin(16sin(6x)))=-1632sin(16sin(6x))cos(6x)\end{align*}\)

Example Question #201 : First And Second Derivatives Of Functions

\(\displaystyle \begin{align*}&\text{Calculate the derivative of the function}\\&-17sin(15sin(x))\end{align*}\)

Possible Answers:

\(\displaystyle -255cos(15sin(x))cos(x)\)

\(\displaystyle -17cos(15sin(x))\)

\(\displaystyle -17sin(15cos(x))\)

\(\displaystyle 15cos(x)\)

Correct answer:

\(\displaystyle -255cos(15sin(x))cos(x)\)

Explanation:

\(\displaystyle \begin{align*}&\text{Our function, }-17sin(15sin(x))\text{, is one function nested within another.}\\&\text{Note the }15sin(x)\text{ inside of the }-17sin()\\&\text{We'll wish to use the chain rule:}\\&(f\circ g )'=(f'\circ g )\cdot g'\\&\text{Along with the following:}\\&d[sin(u)]=cos(u)du\\&u=15sin(x)\\&du=15cos(x)\\&f'(x)=(15cos(x))(-17cos(15sin(x)))=-255cos(15sin(x))cos(x)\end{align*}\)

Example Question #1523 : Calculus Ii

\(\displaystyle \begin{align*}&\text{Find the derivative of the function }\\&f(x)=20e^{(5tan(4x))}\end{align*}\)

Possible Answers:

\(\displaystyle 20e^{(5tan(4x))}\cdot (20tan(4x)^{2} + 20)\)

\(\displaystyle 20tan(4x)^{2} + 20\)

\(\displaystyle 20e^{(20tan(4x)^{2} + 20)}\)

\(\displaystyle 20e^{(5tan(4x))}\)

Correct answer:

\(\displaystyle 20e^{(5tan(4x))}\cdot (20tan(4x)^{2} + 20)\)

Explanation:

\(\displaystyle \begin{align*}&\text{The function }f(x)=20e^{(5tan(4x))}\text{, can be seen as a function nested within another.}\\&\text{Notice the }5tan(4x)\text{ within the }20e^{()}\\&\text{We'll wish to use the chain rule:}\\&(f\circ g )'=(f'\circ g )\cdot g'\\&\text{Along with the following:}\\&d[tan(u)]=\frac{du}{cos^2(u)}=(tan^2(u)+1)du\\&d[e^u]=e^udu\\&u=5tan(4x)\\&du=20tan(4x)^{2} + 20\\&f'(x)=(20tan(4x)^{2} + 20)(20e^{(5tan(4x))})=20e^{(5tan(4x))}\cdot (20tan(4x)^{2} + 20)\end{align*}\)

Example Question #1524 : Calculus Ii

\(\displaystyle \begin{align*}&\text{Find the derivative of the function }\\&f(x)=19tan(17cos(5x))\end{align*}\)

Possible Answers:

\(\displaystyle 19tan(17cos(5x))^{2} + 19\)

\(\displaystyle -1615sin(5x)\cdot (tan(17cos(5x))^{2} + 1)\)

\(\displaystyle -19tan(85sin(5x))\)

\(\displaystyle -85sin(5x)\)

Correct answer:

\(\displaystyle -1615sin(5x)\cdot (tan(17cos(5x))^{2} + 1)\)

Explanation:

\(\displaystyle \begin{align*}&\text{The function }f(x)=19tan(17cos(5x))\text{, can be seen as a function nested within another.}\\&\text{Notice the }17cos(5x)\text{ within the }19tan()\\&\text{We'll wish to use the chain rule:}\\&(f\circ g )'=(f'\circ g )\cdot g'\\&\text{Along with the following:}\\&d[cos(u)]=-sin(u)du\\&d[tan(u)]=\frac{du}{cos^2(u)}=(tan^2(u)+1)du\\&u=17cos(5x)\\&du=-85sin(5x)\\&f'(x)=(-85sin(5x))(19tan(17cos(5x))^{2} + 19)=-1615sin(5x)\cdot (tan(17cos(5x))^{2} + 1)\end{align*}\)

Example Question #202 : First And Second Derivatives Of Functions

\(\displaystyle \begin{align*}&\text{Calculate the derivative of the function}\\&-6sin(4cos(3x))\end{align*}\)

Possible Answers:

\(\displaystyle 6sin(12sin(3x))\)

\(\displaystyle 6sin(12sin(3x))\)

\(\displaystyle 6cos(4cos(3x))\)

\(\displaystyle 72sin(3x)cos(4cos(3x))\)

Correct answer:

\(\displaystyle 72sin(3x)cos(4cos(3x))\)

Explanation:

\(\displaystyle \begin{align*}&\text{Our function, }-6sin(4cos(3x))\text{, is one function nested within another.}\\&\text{Note the }-4cos(3x)\text{ inside of the }6sin()\\&\text{We'll wish to use the chain rule:}\\&(f\circ g )'=(f'\circ g )\cdot g'\\&\text{Along with the following:}\\&d[cos(u)]=-sin(u)du\\&d[sin(u)]=cos(u)du\\&u=-4cos(3x)\\&du=12sin(3x)\\&f'(x)=(12sin(3x))(6cos(4cos(3x)))=72sin(3x)cos(4cos(3x))\end{align*}\)

Example Question #403 : Derivative Review

\(\displaystyle \begin{align*}&\text{Take the derivative with respect to }x\text{ of the function}\\&y=-cos(10tan(5x))\end{align*}\)

Possible Answers:

\(\displaystyle 50tan(5x)^{2} + 50\)

\(\displaystyle sin(10tan(5x))\)

\(\displaystyle -cos(50tan(5x)^{2} + 50)\)

\(\displaystyle sin(10tan(5x))\cdot (50tan(5x)^{2} + 50)\)

Correct answer:

\(\displaystyle sin(10tan(5x))\cdot (50tan(5x)^{2} + 50)\)

Explanation:

\(\displaystyle \begin{align*}&\text{The function }y=-cos(10tan(5x))\text{ consists of two functions, one nested in the other..}\\&\text{In particular, }10tan(5x)\text{ is inside of the }-1cos()\\&\text{We'll wish to use the chain rule:}\\&(f\circ g )'=(f'\circ g )\cdot g'\\&\text{Along with the following:}\\&d[tan(u)]=\frac{du}{cos^2(u)}=(tan^2(u)+1)du\\&d[cos(u)]=-sin(u)du\\&u=10tan(5x)\\&du=50tan(5x)^{2} + 50\\&\frac{dy}{dx}=(50tan(5x)^{2} + 50)(sin(10tan(5x)))=sin(10tan(5x))\cdot (50tan(5x)^{2} + 50)\end{align*}\)

Example Question #404 : Derivative Review

\(\displaystyle \begin{align*}&\text{Take the derivative with respect to }x\text{ of the function}\\&y=4cos(7sin(x))\end{align*}\)

Possible Answers:

\(\displaystyle 4sin(7sin(x))\)

\(\displaystyle -7cos(x)\)

\(\displaystyle 4cos(7cos(x))\)

\(\displaystyle -28sin(7sin(x))cos(x)\)

Correct answer:

\(\displaystyle -28sin(7sin(x))cos(x)\)

Explanation:

\(\displaystyle \begin{align*}&\text{The function }y=4cos(7sin(x))\text{ consists of two functions, one nested in the other..}\\&\text{In particular, }-7sin(x)\text{ is inside of the }4cos()\\&\text{We'll wish to use the chain rule:}\\&(f\circ g )'=(f'\circ g )\cdot g'\\&\text{Along with the following:}\\&d[sin(u)]=cos(u)du\\&d[cos(u)]=-sin(u)du\\&u=-7sin(x)\\&du=-7cos(x)\\&\frac{dy}{dx}=(-7cos(x))(4sin(7sin(x)))=-28sin(7sin(x))cos(x)\end{align*}\)

Example Question #405 : Derivative Review

\(\displaystyle \begin{align*}&\text{Calculate the derivative of the function}\\&10cos(2\cdot 3^x)\end{align*}\)

Possible Answers:

\(\displaystyle -2\cdot 3^xln(3)\)

\(\displaystyle -20\cdot 3^xln(3)sin(2\cdot 3^x)\)

\(\displaystyle 10cos(2\cdot 3^xln(3))\)

\(\displaystyle 10sin(2\cdot 3^x)\)

Correct answer:

\(\displaystyle -20\cdot 3^xln(3)sin(2\cdot 3^x)\)

Explanation:

\(\displaystyle \begin{align*}&\text{Our function, }10cos(2\cdot 3^x)\text{, is one function nested within another.}\\&\text{Note the }-2\cdot 3^x\text{ inside of the }10cos()\\&\text{We'll wish to use the chain rule:}\\&(f\circ g )'=(f'\circ g )\cdot g'\\&\text{Along with the following:}\\&d[a^u]=a^uduln(a)\\&d[cos(u)]=-sin(u)du\\&u=-2\cdot 3^x\\&du=-2\cdot 3^xln(3)\\&f'(x)=(-2\cdot 3^xln(3))(10sin(2\cdot 3^x))=-20\cdot 3^xln(3)sin(2\cdot 3^x)\end{align*}\)

Example Question #406 : Derivative Review

\(\displaystyle \begin{align*}&\text{Take the derivative with respect to }x\text{ of the function}\\&y=5sin(3e^{(6x)})\end{align*}\)

Possible Answers:

\(\displaystyle 5cos(3e^{(6x)})\)

\(\displaystyle 5sin(18e^{(6x)})\)

\(\displaystyle 90e^{(6x)}cos(3e^{(6x)})\)

\(\displaystyle 18e^{(6x)}\)

Correct answer:

\(\displaystyle 90e^{(6x)}cos(3e^{(6x)})\)

Explanation:

\(\displaystyle \begin{align*}&\text{The function }y=5sin(3e^{(6x)})\text{ consists of two functions, one nested in the other..}\\&\text{In particular, }3e^{(6x)}\text{ is inside of the }5sin()\\&\text{We'll wish to use the chain rule:}\\&(f\circ g )'=(f'\circ g )\cdot g'\\&\text{Along with the following:}\\&d[e^u]=e^udu\\&d[sin(u)]=cos(u)du\\&u=3e^{(6x)}\\&du=18e^{(6x)}\\&\frac{dy}{dx}=(18e^{(6x)})(5cos(3e^{(6x)}))=90e^{(6x)}cos(3e^{(6x)})\end{align*}\)

Example Question #203 : First And Second Derivatives Of Functions

The Laplace Transform is an integral transform that converts functions from the time domain \(\displaystyle t\) to the complex frequency domain \(\displaystyle s\). The transformation of a function \(\displaystyle f(t)\) into its Laplace Transform \(\displaystyle F(s)\) is given by:

\(\displaystyle F(s)= \int_{0}^{\infty}e^{-st}*f(t) dt\)

Where \(\displaystyle s=a+bi\), where \(\displaystyle a\) and \(\displaystyle b\) are constants and \(\displaystyle i\) is the imaginary number. 

Determine the value of \(\displaystyle \frac{\mathrm{d} }{\mathrm{d} s}F(s)\)

Possible Answers:

\(\displaystyle tF(s)\)

\(\displaystyle -tF(s)\)

\(\displaystyle f'(t)*F(s)\)

\(\displaystyle -sF(s)\)

Correct answer:

\(\displaystyle -tF(s)\)

Explanation:

\(\displaystyle \frac{\mathrm{d} }{\mathrm{d} s}F(s)= \frac{d}{ds}\int_{0}^{\infty}e^{-st}*f(t) dt=-t*[\int_{0}^{\infty}e^{-st}*f(t) dt]=-tF(s)\)

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