Chapter 2: Problem 37
In Problems \(37-44,\) find the linear approximation to the given functions at the specified points. Plot the function and its linear approximation over the indicated interval. $$ f(x)=x^{2} \text { at } a=2,[0,3] $$
Short Answer
Expert verified
The linear approximation at \( a = 2 \) is \( L(x) = 4x - 4 \).
Step by step solution
01
Find the function's derivative
First, we need to find the derivative of the function \( f(x) = x^2 \). The derivative represents the slope of the tangent line at any point \( x \), which is essential for the linear approximation. The derivative \( f'(x) \) is found by differentiating the function:\[ f'(x) = 2x \].
02
Evaluate the function and derivative at the point of tangency
Next, we need to evaluate the function and its derivative at the specified point \( a = 2 \). This will give us the y-coordinate and the slope at \( x = 2 \), which are needed to form the equation of the tangent line.Calculate \( f(2) \):\[ f(2) = 2^2 = 4 \].Calculate \( f'(2) \):\[ f'(2) = 2 \times 2 = 4 \].
03
Write the equation of the tangent line
Using the point-slope form of a line \( y - y_1 = m(x - x_1) \), where \( m \) is the slope, \( x_1 = 2 \), and \( y_1 = 4 \), we form the equation of the tangent line.Substitute in the values:\[L(x) = 4 + 4(x - 2)\].Simplifying gives:\[L(x) = 4 + 4x - 8 = 4x - 4\].
04
Plot the function and its linear approximation
In this step, plot both the original function \( f(x) = x^2 \) and its linear approximation \( L(x) = 4x - 4 \) over the interval \([0, 3]\). The function will be a curve, while the linear approximation will be a straight line that touches \( f(x) \) at \( x = 2 \).This visual comparison illustrates how the linear approximation estimates the function near \( x = 2 \).
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Tangent Line
In calculus, the tangent line is like a gentle hand that just touches the curve of a function at one point and shows the direction the curve is heading in at that spot. Imagine standing on a curve; the tangent line tells you the immediate path you'd follow if you kept walking without changing direction. So, what does a tangent line do in the world of calculus? Here’s how it helps in function approximation:
- It provides a straight-line view or linear perspective of a curve's direction at a single point.
- By assessing the tangent, we can understand and predict the behavior of a curve, especially in small neighboring intervals around a specific point.
Derivative
The derivative of a function is an essential tool in calculus used to measure the instantaneous rate of change or the slope at any point on a curve. Much like checking how fast your car is moving at an exact moment, the derivative measures the speed of function changes.
- For the function \( f(x) = x^2 \), the derivative \( f'(x) = 2x \) represents how quickly or slowly the curve of \( f(x) \) rises or falls.
- The value of the derivative at a specific point gives the slope of the tangent line there.
- Finding the derivative is a basic skill needed for solving more complex calculus problems.
Function Approximation
Function approximation is a technique used to find a simple function that closely resembles the behavior of a more complex one. Linear approximation, a type of function approximation, utilizes the tangent line to estimate the value of a function near a particular point.When working with \( f(x) = x^2 \) at \( x = 2 \), we saw how the tangent line (\( L(x) = 4x - 4 \)) serves as a linear approximation:
- The approximation is useful over a small range, giving a simpler equation for quick calculations.
- It helps in making predictions without dealing with complicated functions.
- It’s ideal for scenarios where exactness isn't necessary, and a reasonable estimate suffices.
Calculus Problem Solving
Calculus problem-solving often involves breaking down a complex system into manageable parts, much like solving a puzzle. The goal is to apply calculus tools to approach and solve real-world challenges step by step. Here's how you can tackle calculus problems efficiently:
- Identify the core problem: Determine what you need to find and what information you have.
- Use derivatives to understand rate changes and find slopes of tangent lines.
- Apply linear approximation to simplify and make predictions about the function’s behavior near points of interest.
- Visualize your results by plotting graphs to see the relationship between the function and its approximation.