Lapse rates in the atmosphere Refer to Example 2. Concurrent measurements indicate that at an elevation of 6.1 km, the temperature is -10.3° C and at an elevation of 3.2km , the temperature is 8.0°C . Based on the Mean Value Theorem, can you conclude that the lapse rate exceeds the threshold value of 7°C/ km at some intermediate elevation? Explain.
Table of contents
- 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 Integrals4h 44m
- 9. Graphical Applications of Integrals2h 27m
- 10. Physics Applications of Integrals 2h 22m
4. Applications of Derivatives
Differentials
Problem 2.82.2
Textbook Question
b. Estimate a solution to the equation in the given interval using a root finder.
x^5+7x+5=0; (−1,0)

1
First, understand the problem: We need to find a root of the equation x^5 + 7x + 5 = 0 within the interval (-1, 0). A root finder method, such as the bisection method, can be used to estimate the solution.
Start by evaluating the function at the endpoints of the interval. Calculate f(-1) and f(0) to determine if there is a sign change, which indicates a root exists between these points.
Apply the bisection method: Divide the interval into two halves and evaluate the function at the midpoint. If the function changes sign between the midpoint and one of the endpoints, the root lies in that subinterval.
Continue the bisection process: Repeatedly halve the interval and check for sign changes at the midpoints. This iterative process narrows down the interval where the root is located.
Stop the process when the interval is sufficiently small, or when the function value at the midpoint is close enough to zero, indicating an approximate root of the equation.

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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Root Finding
Root finding is a numerical method used to determine the values of x for which a given function f(x) equals zero. Common techniques include the bisection method, Newton's method, and the secant method. These methods iteratively approximate the root by evaluating the function at specific points and refining the interval or estimate until a satisfactory level of accuracy is achieved.
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Intermediate Value Theorem
The Intermediate Value Theorem states that if a continuous function takes on two values at two points, it must also take on any value between those two points. This theorem is crucial for establishing the existence of roots within a given interval. In the context of the equation x^5 + 7x + 5 = 0, verifying that the function changes sign over the interval (-1, 0) indicates that a root exists within that range.
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Function Behavior and Graphing
Understanding the behavior of the function, including its continuity, increasing or decreasing nature, and critical points, is essential for effective root finding. Graphing the function can provide visual insights into where the function crosses the x-axis, indicating potential roots. Analyzing the function's derivative can also help identify intervals where the function is increasing or decreasing, aiding in the selection of appropriate root-finding methods.
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