- 0. Functions7h 52m
- Introduction to Functions16m
- Piecewise Functions10m
- Properties of Functions9m
- Common Functions1h 8m
- Transformations5m
- Combining Functions27m
- Exponent rules32m
- Exponential Functions28m
- Logarithmic Functions24m
- Properties of Logarithms34m
- Exponential & Logarithmic Equations35m
- Introduction to Trigonometric Functions38m
- Graphs of Trigonometric Functions44m
- Trigonometric Identities47m
- Inverse Trigonometric Functions48m
- 1. Limits and Continuity2h 2m
- 2. Intro to Derivatives1h 33m
- 3. Techniques of Differentiation3h 18m
- 4. Applications of Derivatives2h 38m
- 5. Graphical Applications of Derivatives6h 2m
- 6. Derivatives of Inverse, Exponential, & Logarithmic Functions2h 37m
- 7. Antiderivatives & Indefinite Integrals1h 26m
- 8. Definite Integrals3h 25m
4. Applications of Derivatives
Differentials
Problem 4.24.1
Textbook Question
{Use of Tech} Finding all roots Use Newton’s method to find all the roots of the following functions. Use preliminary analysis and graphing to determine good initial approximations.
f(x) = x⁵/5 - x³/4 - 1/20

1
Step 1: Begin by performing a preliminary analysis of the function f(x) = \frac{x^5}{5} - \frac{x^3}{4} - \frac{1}{20}. Identify the behavior of the function by considering its end behavior and any obvious roots or symmetry. This can be done by analyzing the leading term \frac{x^5}{5}, which suggests that as x approaches positive or negative infinity, f(x) will also approach positive or negative infinity respectively.
Step 2: Graph the function f(x) to visually identify potential roots. Look for points where the graph crosses the x-axis, as these are the x-values where f(x) = 0. Use this graph to make educated guesses for initial approximations of the roots.
Step 3: Apply Newton's method to refine these initial approximations. Newton's method uses the formula x_{n+1} = x_n - \frac{f(x_n)}{f'(x_n)}, where f'(x) is the derivative of f(x). Calculate the derivative f'(x) = x^4 - \frac{3x^2}{4}.
Step 4: Choose an initial approximation x_0 based on the graph and apply the Newton's method formula iteratively. For each iteration, compute x_{n+1} using the current approximation x_n, the function value f(x_n), and the derivative f'(x_n). Repeat this process until the values converge to a stable root.
Step 5: Verify the roots found by substituting them back into the original function f(x) to ensure that they satisfy f(x) = 0. If necessary, adjust the initial approximations and repeat the process to find additional roots, ensuring all roots are identified.
Recommended similar problem, with video answer:

This video solution was recommended by our tutors as helpful for the problem above
Video duration:
6mPlay a video:
Was this helpful?