Chapter 3: Problem 5
Find the linearization \(L(x)\) of \(f(x)\) at \(x=a.\) \(f(x)=\tan x, \quad a=\pi\)
Short Answer
Expert verified
The linearization is \(L(x) = x - \pi\).
Step by step solution
01
Understand the Linearization Formula
The linearization of a function at a point provides an approximation using the tangent line at that point. It is given by the formula:\[ L(x) = f(a) + f'(a)(x-a) \] where \(f(a)\) is the function value at \(x=a\) and \(f'(a)\) is the derivative of the function evaluated at \(x=a\).
02
Calculate the Function Value at \(x = a\)
We need to find \(f(a)\) for \(a = \pi\). The function is \(f(x) = \tan(x)\), so:\[ f(\pi) = \tan(\pi) = 0 \].
03
Compute the Derivative of the Function
The derivative of \(f(x) = \tan(x)\) is \(f'(x) = \sec^2(x)\).
04
Evaluate the Derivative at \(x = a\)
Substitute \(x = \pi\) into the derivative:\[ f'(\pi) = \sec^2(\pi) = 1 \] because \(\sec(\pi) = \frac{1}{\cos(\pi)} = -1\). Thus, \( \sec^2(\pi) = (-1)^2 = 1 \).
05
Construct the Linearization \(L(x)\)
Using the linearization formula:\[ L(x) = f(\pi) + f'(\pi)(x - \pi) \]\[ L(x) = 0 + 1(x - \pi) \]Thus, the linear approximation \(L(x)\) is:\[ L(x) = x - \pi \].
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Tangent Line Approximation
Linearization of a function through tangent line approximation is a fundamental concept to approximate a function around a specific point. Imagine you have a curve representing a function, and you want to understand its behavior around a particular point without dealing with the complexities of the curve itself.
This is where the tangent line comes into play. It's a straight line that just touches the curve at that point, reflecting the slope and direction of the function at that exact spot.
By using the formula:
For instance, for \( f(x) = \tan(x) \) at \( x = \pi \), the tangent line approximation gives us a simple linear expression \( L(x) = x - \pi \).
By replacing \( x \) with values near \( \pi \), you can estimate \( \tan(x) \) without complicated calculations.
This is where the tangent line comes into play. It's a straight line that just touches the curve at that point, reflecting the slope and direction of the function at that exact spot.
By using the formula:
- \( L(x) = f(a) + f'(a)(x-a) \)
For instance, for \( f(x) = \tan(x) \) at \( x = \pi \), the tangent line approximation gives us a simple linear expression \( L(x) = x - \pi \).
By replacing \( x \) with values near \( \pi \), you can estimate \( \tan(x) \) without complicated calculations.
Derivative Evaluation
Understanding derivative evaluation is crucial in building the linearization of a function. The derivative represents the rate of change or the slope of the function at a particular point.
To compute the linear approximation, we need to evaluate the derivative \( f'(x) \) at \( x = a \).
Here’s a step-by-step method:
Through derivative evaluation, such as with \( \tan \), it becomes evident how changes around a point are modeled accurately, simplifying complex analyses.
To compute the linear approximation, we need to evaluate the derivative \( f'(x) \) at \( x = a \).
Here’s a step-by-step method:
- Identify the original function, say \( f(x) = \tan(x) \).
- Calculate the derivative, which for \( \tan(x) \) is \( f'(x) = \sec^2(x) \).
- Substitute \( x = a \) into this derivative to find \( f'(a) \), e.g., \( f'(\pi) = \sec^2(\pi) = 1 \).
Through derivative evaluation, such as with \( \tan \), it becomes evident how changes around a point are modeled accurately, simplifying complex analyses.
Trigonometric Functions
Trigonometric functions, like \( \tan(x) \), play a significant role in a wide range of mathematical applications. These functions relate the angles of a triangle to the lengths of its sides, but they also serve well in various calculus concepts.
Key aspects:
Key aspects:
- \( \tan(x) \), the tangent function, represents the ratio of the opposite side to the adjacent side in a right triangle.
- Its properties and periodic behavior make it useful in wave patterns and oscillations.
- The derivative, \( \sec^2(x) \), reflects the rate at which the tangent function changes, instrumental in understanding the function’s behavior near specific points.