Calculus 3 : Calculus 3

Study concepts, example questions & explanations for Calculus 3

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Example Questions

Example Question #543 : Partial Derivatives

\(\displaystyle \begin{align*}&\text{Perform the partial derivation, }f_{zyy}\\&\text{Where }f(x,y,z)=\frac{{(3^{(x^2)}e^{(y)})}}{z^2}\end{align*}\)

Possible Answers:

\(\displaystyle {\frac{-{(2\cdot3^{(x^2)}e^{(y)})}}{z^3}}\)

\(\displaystyle {\frac{-{(2\cdot3^{(3x^2)}e^{(3y)})}}{z^7}}\)

\(\displaystyle {\frac{{(2\cdot3^{(x^2)}e^{(y)})}}{z^2} -\frac{ {(2\cdot3^{(x^2)}e^{(y)})}}{z^3}}\)

\(\displaystyle {\frac{-{(8\cdot3^{(3x^2)}e^{(3y)})}}{z^9}}\)

Correct answer:

\(\displaystyle {\frac{-{(2\cdot3^{(x^2)}e^{(y)})}}{z^3}}\)

Explanation:

\(\displaystyle \begin{align*}&\text{When taking partial derivatives, order does not matter; you can}\\&\text{simply treat any variable that you're not deriving the equation for as constant.}\\&\text{Utilizing derivative rules:}\\&d[uv]=udv+vdu\\&(f\circ g )'=(f'\circ g )\cdot g'\\&d[e^u]=e^udu\\&\text{Solve step-by-step:}\\&f(x,y,z)=\frac{{(3^{(x^2)}e^{(y)})}}{z^2}\\&f_{z}=\frac{-{(2\cdot3^{(x^2)}e^{(y)})}}{z^3}\\&f_{zy}=\frac{-{(2\cdot3^{(x^2)}e^{(y)})}}{z^3}\\&f_{zyy}=\frac{-{(2\cdot3^{(x^2)}e^{(y)})}}{z^3}\end{align*}\)

Example Question #541 : Partial Derivatives

\(\displaystyle \begin{align*}&\text{Perform the partial derivation, }f_{zxx}\\&\text{Where }f(x,y,z)=6x^2sin{(4z)}e^{(4y)}\end{align*}\)

Possible Answers:

\(\displaystyle {55296x^3cos{(4z)}^3e^{(12y)}}\)

\(\displaystyle {3456x^4cos{(4z)}sin{(4z)}^2e^{(12y)}}\)

\(\displaystyle {48cos{(4z)}e^{(4y)}}\)

\(\displaystyle {24xsin{(4z)}e^{(4y)} + 24x^2cos{(4z)}e^{(4y)}}\)

Correct answer:

\(\displaystyle {48cos{(4z)}e^{(4y)}}\)

Explanation:

\(\displaystyle \begin{align*}&\text{When taking partial derivatives, order does not matter; you can}\\&\text{simply treat any variable that you're not deriving the equation for as constant.}\\&\text{Utilizing derivative rules:}\\&d[uv]=udv+vdu\\&(f\circ g )'=(f'\circ g )\cdot g'\\&d[sin(u)]=cos(u)du\\&\text{Solve step-by-step:}\\&f(x,y,z)=6x^2sin{(4z)}e^{(4y)}\\&f_{z}=24x^2cos{(4z)}e^{(4y)}\\&f_{zx}=48xcos{(4z)}e^{(4y)}\\&f_{zxx}=48cos{(4z)}e^{(4y)}\end{align*}\)

Example Question #545 : Partial Derivatives

\(\displaystyle \begin{align*}&\text{Perform the partial derivation, }f_{zz}\\&\text{Where }f(x,y,z)=\frac{-{(y^2ln{(z)})}}{{(3x^2)}}\end{align*}\)

Possible Answers:

\(\displaystyle {\frac{y^4}{{(9x^4z^2)}}}\)

\(\displaystyle {\frac{-{(2y^2)}}{{(3x^2z)}}}\)

\(\displaystyle {\frac{-y^4}{{(9x^4z^3)}}}\)

\(\displaystyle {\frac{y^2}{{(3x^2z^2)}}}\)

Correct answer:

\(\displaystyle {\frac{y^2}{{(3x^2z^2)}}}\)

Explanation:

\(\displaystyle \begin{align*}&\text{When taking partial derivatives, order does not matter; you can}\\&\text{simply treat any variable that you're not deriving the equation for as constant.}\\&\text{Utilizing derivative rules:}\\&d[uv]=udv+vdu\\&(f\circ g )'=(f'\circ g )\cdot g'\\&d[ln(u)]=\frac{du}{u}\\&\text{Solve step-by-step:}\\&f(x,y,z)=\frac{-{(y^2ln{(z)})}}{{(3x^2)}}\\&f_{z}=\frac{-y^2}{{(3x^2z)}}\\&f_{zz}=\frac{y^2}{{(3x^2z^2)}}\end{align*}\)

Example Question #546 : Partial Derivatives

\(\displaystyle \begin{align*}&\text{Perform the partial derivation, }f_{zyzy}\\&\text{Where }f(x,y,z)=\frac{-{(2ln{(4z)}e^{(3x)}e^{(y)})}}{9}\end{align*}\)

Possible Answers:

\(\displaystyle {\frac{{(16e^{(12x)}e^{(4y)})}}{{(6561z^6)}}}\)

\(\displaystyle {\frac{{(2e^{(3x)}e^{(y)})}}{{(9z^2)}}}\)

\(\displaystyle {-\frac{ {(4e^{(3x)}e^{(y)})}}{{(9z)}} -\frac{ {(4ln{(4z)}e^{(3x)}e^{(y)})}}{9}}\)

\(\displaystyle {\frac{{(16ln{(4z)}^2e^{(12x)}e^{(4y)})}}{{(6561z^2)}}}\)

Correct answer:

\(\displaystyle {\frac{{(2e^{(3x)}e^{(y)})}}{{(9z^2)}}}\)

Explanation:

\(\displaystyle \begin{align*}&\text{When taking partial derivatives, order does not matter; you can}\\&\text{simply treat any variable that you're not deriving the equation for as constant.}\\&\text{Utilizing derivative rules:}\\&d[uv]=udv+vdu\\&(f\circ g )'=(f'\circ g )\cdot g'\\&d[ln(u)]=\frac{du}{u}\\&d[e^u]=e^udu\\&\text{Solve step-by-step:}\\&f(x,y,z)=\frac{-{(2ln{(4z)}e^{(3x)}e^{(y)})}}{9}\\&f_{z}=\frac{-{(2e^{(3x)}e^{(y)})}}{{(9z)}}\\&f_{zy}=\frac{-{(2e^{(3x)}e^{(y)})}}{{(9z)}}\\&f_{zyz}=\frac{{(2e^{(3x)}e^{(y)})}}{{(9z^2)}}\\&f_{zyzy}=\frac{{(2e^{(3x)}e^{(y)})}}{{(9z^2)}}\end{align*}\)

Example Question #547 : Partial Derivatives

\(\displaystyle \begin{align*}&\text{Perform the partial derivation, }f_{zzxz}\\&\text{Where }f(x,y,z)=\frac{-{(x^2cos{(y^2)}cos{(z)})}}{3}\end{align*}\)

Possible Answers:

\(\displaystyle {x^2cos{(y^2)}sin{(z)} -\frac{ {(2xcos{(y^2)}cos{(z)})}}{3}}\)

\(\displaystyle {\frac{-{(2x^7cos{(y^2)}^4cos{(z)}sin{(z)}^3)}}{81}}\)

\(\displaystyle {\frac{-{(4x^6cos{(y^2)}^4cos{(z)}^2sin{(z)}^2)}}{81}}\)

\(\displaystyle {\frac{-{(2xcos{(y^2)}sin{(z)})}}{3}}\)

Correct answer:

\(\displaystyle {\frac{-{(2xcos{(y^2)}sin{(z)})}}{3}}\)

Explanation:

\(\displaystyle \begin{align*}&\text{When taking partial derivatives, order does not matter; you can}\\&\text{simply treat any variable that you're not deriving the equation for as constant.}\\&\text{Utilizing derivative rules:}\\&d[uv]=udv+vdu\\&(f\circ g )'=(f'\circ g )\cdot g'\\&d[cos(u)]=-sin(u)du\\&d[sin(u)]=cos(u)du\\&\text{Solve step-by-step:}\\&f(x,y,z)=\frac{-{(x^2cos{(y^2)}cos{(z)})}}{3}\\&f_{z}=\frac{{(x^2cos{(y^2)}sin{(z)})}}{3}\\&f_{zz}=\frac{{(x^2cos{(y^2)}cos{(z)})}}{3}\\&f_{zzx}=\frac{{(2xcos{(y^2)}cos{(z)})}}{3}\\&f_{zzxz}=\frac{-{(2xcos{(y^2)}sin{(z)})}}{3}\end{align*}\)

Example Question #548 : Partial Derivatives

\(\displaystyle \begin{align*}&\text{Perform the partial derivation, }f_{xy}\\&\text{Where }f(x,y,z)=\frac{{(2cos{(z)}ln{(x)})}}{{(9y)}}\end{align*}\)

Possible Answers:

\(\displaystyle {\frac{-{(4cos{(z)}^2ln{(x)})}}{{(81xy^3)}}}\)\(\displaystyle {\frac{-{(4cos{(z)}^2ln{(x)})}}{{(81xy^3)}}}\)

\(\displaystyle {\frac{{(2cos{(z)})}}{{(9xy)}} -\frac{ {(2cos{(z)}ln{(x)})}}{{(9y^2)}}}\)

\(\displaystyle {\frac{-{(4cos{(z)}^2)}}{{(81x^2y^3)}}}\)

\(\displaystyle {\frac{-{(2cos{(z)})}}{{(9xy^2)}}}\)

Correct answer:

\(\displaystyle {\frac{-{(2cos{(z)})}}{{(9xy^2)}}}\)

Explanation:

\(\displaystyle \begin{align*}&\text{When taking partial derivatives, order does not matter; you can}\\&\text{simply treat any variable that you're not deriving the equation for as constant.}\\&\text{Utilizing derivative rules:}\\&d[uv]=udv+vdu\\&(f\circ g )'=(f'\circ g )\cdot g'\\&d[ln(u)]=\frac{du}{u}\\&\text{Solve step-by-step:}\\&f(x,y,z)=\frac{{(2cos{(z)}ln{(x)})}}{{(9y)}}\\&f_{x}=\frac{{(2cos{(z)})}}{{(9xy)}}\\&f_{xy}=\frac{-{(2cos{(z)})}}{{(9xy^2)}}\end{align*}\)\(\displaystyle \begin{align*}&\text{When taking partial derivatives, order does not matter; you can}\\&\text{simply treat any variable that you're not deriving the equation for as constant.}\\&\text{Utilizing derivative rules:}\\&d[uv]=udv+vdu\\&(f\circ g )'=(f'\circ g )\cdot g'\\&d[ln(u)]=\frac{du}{u}\\&\text{Solve step-by-step:}\\&f(x,y,z)=\frac{{(2cos{(z)}ln{(x)})}}{{(9y)}}\\&f_{x}=\frac{{(2cos{(z)})}}{{(9xy)}}\\&f_{xy}=\frac{-{(2cos{(z)})}}{{(9xy^2)}}\end{align*}\)

Example Question #549 : Partial Derivatives

\(\displaystyle \begin{align*}&\text{Perform the partial derivation, }f_{xyx}\\&\text{Where }f(x,y,z)=\frac{-{(2\cdot2^{(x^2)}\cdot2^ye^{(4z)})}}{5}\end{align*}\)

Possible Answers:

\(\displaystyle {\frac{ {(2\cdot2^{(x^2)}\cdot2^ye^{(4z)}ln{(2)})}}{5} +\frac{ {(8\cdot2^{(x^2)}\cdot2^yxe^{(4z)}ln{(2)})}}{5}}\)

\(\displaystyle {-\frac{ {(2\cdot2^{(x^2)}\cdot2^ye^{(4z)}ln{(2)})}}{5} -\frac{ {(8\cdot2^{(x^2)}\cdot2^yxe^{(4z)}ln{(2)})}}{5}}\)

\(\displaystyle {-\frac{ {(4\cdot2^{(x^2)}\cdot2^ye^{(4z)}ln{(2)}^2)}}{5} -\frac{ {(8\cdot2^{(x^2)}\cdot2^yx^2e^{(4z)}ln{(2)}^3)}}{5}}\)

\(\displaystyle {\frac{-{(32\cdot2^{(3y)}\cdot2^{(3x^2)}x^2e^{(12z)}ln{(2)}^3)}}{125}}\)

Correct answer:

\(\displaystyle {-\frac{ {(4\cdot2^{(x^2)}\cdot2^ye^{(4z)}ln{(2)}^2)}}{5} -\frac{ {(8\cdot2^{(x^2)}\cdot2^yx^2e^{(4z)}ln{(2)}^3)}}{5}}\)

Explanation:

\(\displaystyle \begin{align*}&\text{When taking partial derivatives, order does not matter; you can}\\&\text{simply treat any variable that you're not deriving the equation for as constant.}\\&\text{Utilizing derivative rules:}\\&d[uv]=udv+vdu\\&(f\circ g )'=(f'\circ g )\cdot g'\\&d[a^u]=a^uduln(a)\\&\text{Solve step-by-step:}\\&f(x,y,z)=\frac{-{(2\cdot2^{(x^2)}\cdot2^ye^{(4z)})}}{5}\\&f_{x}=\frac{-{(4\cdot2^{(x^2)}\cdot2^yxe^{(4z)}ln{(2)})}}{5}\\&f_{xy}=\frac{-{(4\cdot2^{(x^2)}\cdot2^yxe^{(4z)}ln{(2)}^2)}}{5}\\&f_{xyx}=-\frac{ {(4\cdot2^{(x^2)}\cdot2^ye^{(4z)}ln{(2)}^2)}}{5} -\frac{ {(8\cdot2^{(x^2)}\cdot2^yx^2e^{(4z)}ln{(2)}^3)}}{5}\end{align*}\)

Example Question #550 : Partial Derivatives

\(\displaystyle \begin{align*}&\text{Perform the partial derivation, }f_{xyzx}\\&\text{Where }f(x,y,z)=\frac{{(9x^2z^2ln{(y)})}}{2}\end{align*}\)

Possible Answers:

\(\displaystyle {\frac{{(18z)}}{y}}\)

\(\displaystyle {\frac{{(6561x^6z^7ln{(y)}^3)}}{{(2y)}}}\)

\(\displaystyle {18xz^2ln{(y)} + 9x^2zln{(y)} +\frac{ {(9x^2z^2)}}{{(2y)}}}\)

\(\displaystyle {\frac{{(26244x^3z^6ln{(y)})}}{y^3}}\)

Correct answer:

\(\displaystyle {\frac{{(18z)}}{y}}\)

Explanation:

\(\displaystyle \begin{align*}&\text{When taking partial derivatives, order does not matter; you can}\\&\text{simply treat any variable that you're not deriving the equation for as constant.}\\&\text{Utilizing derivative rules:}\\&d[uv]=udv+vdu\\&(f\circ g )'=(f'\circ g )\cdot g'\\&d[ln(u)]=\frac{du}{u}\\&\text{Solve step-by-step:}\\&f(x,y,z)=\frac{{(9x^2z^2ln{(y)})}}{2}\\&f_{x}=9xz^2ln{(y)}\\&f_{xy}=\frac{{(9xz^2)}}{y}\\&f_{xyz}=\frac{{(18xz)}}{y}\\&f_{xyzx}=\frac{{(18z)}}{y}\end{align*}\)

Example Question #551 : Partial Derivatives

\(\displaystyle \begin{align*}&\text{Perform the partial derivation, }f_{xyxy}\\&\text{Where }f(x,y,z)=\frac{{(2e^{(4x)}e^{(z^2)})}}{{(7y^2)}}\end{align*}\)

Possible Answers:

\(\displaystyle {\frac{{(1572864e^{(16x)}e^{(4z^2)})}}{{(2401y^{12})}}}\)

\(\displaystyle {\frac{{(192e^{(4x)}e^{(z^2)})}}{{(7y^4)}}}\)

\(\displaystyle {\frac{{(1024e^{(16x)}e^{(4z^2)})}}{{(2401y^{10})}}}\)

\(\displaystyle {\frac{{(16e^{(4x)}e^{(z^2)})}}{{(7y^2)}} -\frac{ {(8e^{(4x)}e^{(z^2)})}}{{(7y^3)}}}\)

Correct answer:

\(\displaystyle {\frac{{(192e^{(4x)}e^{(z^2)})}}{{(7y^4)}}}\)

Explanation:

\(\displaystyle \begin{align*}&\text{When taking partial derivatives, order does not matter; you can}\\&\text{simply treat any variable that you're not deriving the equation for as constant.}\\&\text{Utilizing derivative rules:}\\&d[uv]=udv+vdu\\&(f\circ g )'=(f'\circ g )\cdot g'\\&d[e^u]=e^udu\\&\text{Solve step-by-step:}\\&f(x,y,z)=\frac{{(2e^{(4x)}e^{(z^2)})}}{{(7y^2)}}\\&f_{x}=\frac{{(8e^{(4x)}e^{(z^2)})}}{{(7y^2)}}\\&f_{xy}=\frac{-{(16e^{(4x)}e^{(z^2)})}}{{(7y^3)}}\\&f_{xyx}=\frac{-{(64e^{(4x)}e^{(z^2)})}}{{(7y^3)}}\\&f_{xyxy}=\frac{{(192e^{(4x)}e^{(z^2)})}}{{(7y^4)}}\end{align*}\)

Example Question #552 : Partial Derivatives

\(\displaystyle \begin{align*}&\text{Perform the partial derivation, }f_{zyzx}\\&\text{Where }f(x,y,z)=\frac{{(2^{(4x)}z^2e^{(4y)})}}{5}\end{align*}\)

Possible Answers:

\(\displaystyle {\frac{{(4096\cdot2^{(16x)}z^2e^{(16y)}ln{(2)})}}{625}}\)

\(\displaystyle {\frac{{(64\cdot2^{(16x)}z^6e^{(16y)}ln{(2)})}}{625}}\)

\(\displaystyle {\frac{{(4\cdot2^{(4x)}ze^{(4y)})}}{5} +\frac{ {(4\cdot2^{(4x)}z^2e^{(4y)})}}{5} +\frac{ {(4\cdot2^{(4x)}z^2e^{(4y)}ln{(2)})}}{5}}\)

\(\displaystyle {\frac{{(32\cdot2^{(4x)}e^{(4y)}ln{(2)})}}{5}}\)

Correct answer:

\(\displaystyle {\frac{{(32\cdot2^{(4x)}e^{(4y)}ln{(2)})}}{5}}\)

Explanation:

\(\displaystyle \begin{align*}&\text{When taking partial derivatives, order does not matter; you can}\\&\text{simply treat any variable that you're not deriving the equation for as constant.}\\&\text{Utilizing derivative rules:}\\&d[uv]=udv+vdu\\&(f\circ g )'=(f'\circ g )\cdot g'\\&d[e^u]=e^udu\\&d[a^u]=a^uduln(a)\\&\text{Solve step-by-step:}\\&f(x,y,z)=\frac{{(2^{(4x)}z^2e^{(4y)})}}{5}\\&f_{z}=\frac{{(2\cdot2^{(4x)}ze^{(4y)})}}{5}\\&f_{zy}=\frac{{(8\cdot2^{(4x)}ze^{(4y)})}}{5}\\&f_{zyz}=\frac{{(8\cdot2^{(4x)}e^{(4y)})}}{5}\\&f_{zyzx}=\frac{{(32\cdot2^{(4x)}e^{(4y)}ln{(2)})}}{5}\end{align*}\)

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