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Ch. 4 - Applications of the Derivative
Briggs - Calculus: Early Transcendentals 3rd Edition
Briggs3rd EditionCalculus: Early TranscendentalsISBN: 9780136847243Not the one you use?Change textbook
Chapter 4, Problem 4.6.45

Use linear approximations to estimate the following quantities. Choose a value of a to produce a small error.
1/³√510

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1
Identify the function that needs to be approximated. In this case, we are dealing with the cube root function, so let \( f(x) = x^{-1/3} \).
Choose a value of \( a \) that is close to 510 and makes the calculation simple. A good choice here is \( a = 512 \) because 512 is a perfect cube (\( 8^3 = 512 \)).
Find the derivative of the function \( f(x) = x^{-1/3} \). The derivative is \( f'(x) = -\frac{1}{3}x^{-4/3} \).
Use the linear approximation formula \( L(x) = f(a) + f'(a)(x - a) \) to estimate \( f(510) \). Calculate \( f(512) \) and \( f'(512) \), then substitute these values into the formula.
Substitute \( x = 510 \) into the linear approximation \( L(x) \) to estimate \( 1/\sqrt[3]{510} \). This will give you the approximate value using the linear approximation method.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Linear Approximation

Linear approximation is a method used to estimate the value of a function near a given point using the tangent line at that point. It is based on the idea that a function can be closely approximated by a linear function when the input is near a specific value. The formula for linear approximation is f(x) ≈ f(a) + f'(a)(x - a), where 'a' is the point of tangency.
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Derivative

The derivative of a function at a point measures the rate at which the function's value changes as its input changes. It is a fundamental concept in calculus that provides the slope of the tangent line to the function at that point. In the context of linear approximation, the derivative is used to determine the slope of the tangent line, which is essential for estimating function values.
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Cube Root Function

The cube root function, denoted as f(x) = x^(1/3), is the inverse of the cube function. It is important in this problem because we are estimating the cube root of a number (in this case, 510). Understanding the behavior of the cube root function, including its continuity and differentiability, is crucial for applying linear approximation effectively.
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