Calculus 1 : How to find differential functions

Study concepts, example questions & explanations for Calculus 1

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Example Questions

Example Question #551 : How To Find Differential Functions

Find the derivative of \(\displaystyle g(x) = \sqrt{x^3+5}\)

Possible Answers:

\(\displaystyle \frac{1}{2\sqrt{x^3+5}}\)

\(\displaystyle -3x^2 \sqrt{x^3+5}\)

\(\displaystyle \frac{3x^2}{2\sqrt{x^3+5}}\)

\(\displaystyle \frac{6x}{2\sqrt{x^3+5}}\)

Correct answer:

\(\displaystyle \frac{3x^2}{2\sqrt{x^3+5}}\)

Explanation:

Rewrite the square root as the \(\displaystyle \small \frac{1}{2}\) power to apply the power rule more easily. Then be sure to use the chain rule to fully differentiate.

Example Question #552 : How To Find Differential Functions

Find the derviative of \(\displaystyle f(x) = \sqrt{\ln{x}}\)

Possible Answers:

\(\displaystyle \small \frac{1}{\sqrt{\ln{x}}}\)

\(\displaystyle \frac{1}{2x}\)

\(\displaystyle \small \frac{1}{2x \sqrt{\ln{x}}}\)

\(\displaystyle - \frac{1}{2x}\)

\(\displaystyle \sqrt{\frac{1}{x}}\)

Correct answer:

\(\displaystyle \small \frac{1}{2x \sqrt{\ln{x}}}\)

Explanation:

Apply the Chain Rule to the function \(\displaystyle \small \small f(x) = (\ln{x})^{\frac{1}{2}}\)

This gives \(\displaystyle \small \frac{1}{2} (\ln{x})^{-\frac{1}{2}} \cdot \frac{1}{x}\). Simplify.

Example Question #553 : Other Differential Functions

The expression of a particular function is unknown; however, we have an expression for its derivative. Knowing that \(\displaystyle f'(x)=csc(cot(x))\) and \(\displaystyle y(2)=4\), approximate \(\displaystyle y(2.04)\) using Euler's Method and four steps.

Possible Answers:

\(\displaystyle 4.019\)

\(\displaystyle 3.912\)

\(\displaystyle 3.749\)

\(\displaystyle 3.888\)

\(\displaystyle 3.996\)

Correct answer:

\(\displaystyle 3.912\)

Explanation:

The general form of Euler's method, when a derivative function, initial value, and step size are known, is:

\(\displaystyle y_n=y_{n+1} +\Delta x f'(x_n,y_n)\)

To calculate the step size find the distance between the final and initial \(\displaystyle x\) value and divide by the number of steps to be used:

\(\displaystyle \Delta x = \frac{x_f-x_i}{Steps}\)

For this problem, we are told \(\displaystyle f'(x)=csc(cot(x))\) and \(\displaystyle y(2)=4\)

Knowing this, we may take the steps to estimate our function value at our final \(\displaystyle x\) value:

\(\displaystyle \Delta x = \frac{2.04-2}{4}=0.01\)

 

\(\displaystyle y_0=4;x_0=2\)

\(\displaystyle y_1=4+(0.01)csc(cot(2))=3.977\)

\(\displaystyle y_2=3.977+(0.01)csc(cot(2.01))=3.955\)

\(\displaystyle y_3=3.955+(0.01)csc(cot(2.02))=3.933\)

\(\displaystyle y_4=3.933+(0.01)csc(cot(2.03))=3.912\)

Example Question #554 : How To Find Differential Functions

The expression of a particular function is unknown; however, we have an expression for its derivative. Knowing that \(\displaystyle f'(x)=sin(2^{e^{x}})\) and \(\displaystyle y(3)=2\), approximate \(\displaystyle y(6)\) using Euler's Method and three steps.

Possible Answers:

\(\displaystyle 0.383\)

\(\displaystyle 1.063\)

\(\displaystyle 0.915\)

\(\displaystyle 1.561\)

\(\displaystyle 2.147\)

Correct answer:

\(\displaystyle 1.063\)

Explanation:

The general form of Euler's method, when a derivative function, initial value, and step size are known, is:

\(\displaystyle y_n=y_{n+1} +\Delta x f'(x_n,y_n)\)

To calculate the step size find the distance between the final and initial \(\displaystyle x\) value and divide by the number of steps to be used:

\(\displaystyle \Delta x = \frac{x_f-x_i}{Steps}\)

For this problem, we are told \(\displaystyle f'(x)=sin(2^{e^{x}})\) and \(\displaystyle y(3)=2\)

Knowing this, we may take the steps to estimate our function value at our final \(\displaystyle x\) value:

\(\displaystyle \Delta x = \frac{6-3}{3}=1\)

\(\displaystyle y_0=2,x_0=3\)

\(\displaystyle y_1=2+(1)sin(2^{e^{3}})=1.326\)

\(\displaystyle y_2=1.326+(1)sin(2^{e^{4}})=0.916\)

\(\displaystyle y_3=0.916+(1)sin(2^{e^{5}})=1.063\)

Example Question #552 : Other Differential Functions

The expression of a particular function is unknown; however, we have an expression for its derivative. Knowing that \(\displaystyle f'(x)=(cos(x))^{cos(x)}\) and \(\displaystyle y(0)=4\), approximate \(\displaystyle y(1.5)\) using Euler's Method and three steps.

Possible Answers:

\(\displaystyle 4.783\)

\(\displaystyle 5.112\)

\(\displaystyle 4.292\)

\(\displaystyle 5.305\)

\(\displaystyle 5.496\)

Correct answer:

\(\displaystyle 5.305\)

Explanation:

The general form of Euler's method, when a derivative function, initial value, and step size are known, is:

\(\displaystyle y_n=y_{n+1} +\Delta x f'(x_n,y_n)\)

To calculate the step size find the distance between the final and initial \(\displaystyle x\) value and divide by the number of steps to be used:

\(\displaystyle \Delta x = \frac{x_f-x_i}{Steps}\)

For this problem, we are told \(\displaystyle f'(x)=(cos(x))^{cos(x)}\) and \(\displaystyle y(0)=4\)

Knowing this, we may take the steps to estimate our function value at our final \(\displaystyle x\) value:

\(\displaystyle \Delta x = \frac{1.5-0}{3}=0.5\)

\(\displaystyle y_0=4,x_0=0\)

\(\displaystyle y_1=4+0.5(cos(0))^{cos(0)}=4.5\)

\(\displaystyle y_2=4.5+0.5(cos(0.5))^{cos(0.5)}=4.946\)

\(\displaystyle y_3=4.946+0.5(cos(1))^{cos(1)}=5.305\)

 

Example Question #1772 : Calculus

The expression of a particular function is unknown; however, we have an expression for its derivative. Knowing that \(\displaystyle f'(x)=cot(x^2)\) and \(\displaystyle y(1)=5\), approximate \(\displaystyle y(1.6)\) using Euler's Method and three steps.

Possible Answers:

\(\displaystyle 5.276\)

\(\displaystyle 4.938\)

\(\displaystyle 5.191\)

\(\displaystyle 5.072\)

\(\displaystyle 5.409\)

Correct answer:

\(\displaystyle 5.072\)

Explanation:

The general form of Euler's method, when a derivative function, initial value, and step size are known, is:

\(\displaystyle y_n=y_{n+1} +\Delta x f'(x_n,y_n)\)

To calculate the step size find the distance between the final and initial \(\displaystyle x\) value and divide by the number of steps to be used:

\(\displaystyle \Delta x = \frac{x_f-x_i}{Steps}\)

For this problem, we are told \(\displaystyle f'(x)=cot(x^2)\) and \(\displaystyle y(1)=5\)

Knowing this, we may take the steps to estimate our function value at our final \(\displaystyle x\) value:

\(\displaystyle \Delta x = \frac{1.6-1}{3}=0.2\)

\(\displaystyle y_0=5,x_0=1\)

\(\displaystyle y_1=5+(0.2)cot(1^2)=5.128\)

\(\displaystyle y_2=5.128+(0.2)cot(1.2^2)=5.154\)

\(\displaystyle y_3=5.154+(0.2)cot(1.4^2)=5.072\)

Example Question #1773 : Calculus

The expression of a particular function is unknown; however, we have an expression for its derivative. Knowing that \(\displaystyle f'(x)=tan(ln(ln(x)))\) and \(\displaystyle y(2)=0\), approximate \(\displaystyle y(5)\) using Euler's Method and three steps.

Possible Answers:

\(\displaystyle -0.265\)

\(\displaystyle 0.049\)

\(\displaystyle -0.517\)

\(\displaystyle 0.183\)

\(\displaystyle -0.384\)

Correct answer:

\(\displaystyle 0.049\)

Explanation:

The general form of Euler's method, when a derivative function, initial value, and step size are known, is:

\(\displaystyle y_n=y_{n+1} +\Delta x f'(x_n,y_n)\)

To calculate the step size find the distance between the final and initial \(\displaystyle x\) value and divide by the number of steps to be used:

\(\displaystyle \Delta x = \frac{x_f-x_i}{Steps}\)

For this problem, we are told \(\displaystyle f'(x)=tan(ln(ln(x)))\) and \(\displaystyle y(2)=0\)

Knowing this, we may take the steps to estimate our function value at our final \(\displaystyle x\) value:

\(\displaystyle \Delta x = \frac{5-2}{3}=1\)

\(\displaystyle y_0=0;x_0=2\)

\(\displaystyle y_1=0+(1)tan(ln(ln(2)))=-0.384\)

\(\displaystyle y_2=-0.384+(1)tan(ln(ln(3)))=-0.290\)

\(\displaystyle y_3=-0.290+(1)tan(ln(ln(4)))=0.049\)

Example Question #1774 : Calculus

The expression of a particular function is unknown; however, we have an expression for its derivative. Knowing that \(\displaystyle f'(x)=sec(x^4)\) and \(\displaystyle y(1)=10\), approximate \(\displaystyle y(2)\) using Euler's Method and four steps.

Possible Answers:

\(\displaystyle 10.615\)

\(\displaystyle 10.725\)

\(\displaystyle 10.515\)

\(\displaystyle 10.983\)

\(\displaystyle 10.422\)

Correct answer:

\(\displaystyle 10.615\)

Explanation:

The general form of Euler's method, when a derivative function, initial value, and step size are known, is:

\(\displaystyle y_n=y_{n+1} +\Delta x f'(x_n,y_n)\)

To calculate the step size find the distance between the final and initial \(\displaystyle x\) value and divide by the number of steps to be used:

\(\displaystyle \Delta x = \frac{x_f-x_i}{Steps}\)

For this problem, we are told\(\displaystyle f'(x)=sec(x^4)\) and \(\displaystyle y(1)=10\)

Knowing this, we may take the steps to estimate our function value at our final \(\displaystyle x\) value:

\(\displaystyle \Delta x = \frac{2-1}{4}=0.25\)

\(\displaystyle y_0=10;x_0=1\)

\(\displaystyle y_1=10+(0.25)sec(1^4)=10.463\)

\(\displaystyle y_2=10.463+(0.25)sec(1.25^4)=10.136\)

\(\displaystyle y_3=10.136+(0.25)sec(1.5^4)=10.865\)

\(\displaystyle y_4=10.865+(0.25)sec(1.75^4)=10.615\)

Example Question #1775 : Calculus

The expression of a particular function is unknown; however, we have an expression for its derivative. Knowing that \(\displaystyle f'(x)=csc(2^x)\) and \(\displaystyle y(1)=3\), approximate \(\displaystyle y(5)\) using Euler's Method and four steps.

Possible Answers:

\(\displaystyle 1.208\)

\(\displaystyle 3.790\)

\(\displaystyle 4.100\)

\(\displaystyle 2.779\)

\(\displaystyle 0.317\)

Correct answer:

\(\displaystyle 0.317\)

Explanation:

The general form of Euler's method, when a derivative function, initial value, and step size are known, is:

\(\displaystyle y_n=y_{n+1} +\Delta x f'(x_n,y_n)\)

To calculate the step size find the distance between the final and initial \(\displaystyle x\) value and divide by the number of steps to be used:

\(\displaystyle \Delta x = \frac{x_f-x_i}{Steps}\)

For this problem, we are told \(\displaystyle f'(x)=csc(2^x)\) and \(\displaystyle y(1)=3\)

Knowing this, we may take the steps to estimate our function value at our final \(\displaystyle x\) value:

\(\displaystyle \Delta x = \frac{5-1}{4}=1\)

\(\displaystyle y_0=3;x_0=1\)

\(\displaystyle y_1=3+(1)csc(2^1)=4.100\)

\(\displaystyle y_2=4.100+(1)csc(2^2)=2.779\)

\(\displaystyle y_3=2.779+(1)csc(2^3)=3.790\)

\(\displaystyle y_4=3.790+(1)csc(2^4)=0.317\)

Example Question #1776 : Calculus

The expression of a particular function is unknown; however, we have an expression for its derivative. Knowing that \(\displaystyle f'(x)=11^{x^6}\) and \(\displaystyle y(1)=5\), approximate \(\displaystyle y(1.16)\) using Euler's Method and four steps.

Possible Answers:

\(\displaystyle 12.614\)

\(\displaystyle 12.025\)

\(\displaystyle 8.098\)

\(\displaystyle 15.622\)

\(\displaystyle 13.159\)

Correct answer:

\(\displaystyle 12.614\)

Explanation:

The general form of Euler's method, when a derivative function, initial value, and step size are known, is:

\(\displaystyle y_n=y_{n+1} +\Delta x f'(x_n,y_n)\)

To calculate the step size find the distance between the final and initial \(\displaystyle x\) value and divide by the number of steps to be used:

\(\displaystyle \Delta x = \frac{x_f-x_i}{Steps}\)

For this problem, we are told \(\displaystyle f'(x)=11^{x^6}\) and \(\displaystyle y(1)=5\)

Knowing this, we may take the steps to estimate our function value at our final \(\displaystyle x\) value:

\(\displaystyle \Delta x = \frac{1.16-1}{4}=0.04\)

\(\displaystyle y_0=5;x_0=1\)

\(\displaystyle y_1=5+(0.04)11^{1^6}=5.44\)

\(\displaystyle y_2=5.44+(0.04)11^{1.04^6}=6.271\)

\(\displaystyle y_3=6.271+(0.04)11^{1.08^6}=8.068\)

\(\displaystyle y_4=8.068+(0.04)11^{1.12^6}=12.614\)

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