Chapter 4: Problem 16
Find all values of c that satisfy the Mean Value Theorem for Integrals on the given interval. $$ f(x)=x^{2} ; \quad[-1,1] $$
Short Answer
Expert verified
The values of \(c\) are \(c = \pm\frac{1}{\sqrt{3}}\).
Step by step solution
01
Understand the Mean Value Theorem for Integrals
The Mean Value Theorem for Integrals states that if a function is continuous on a closed interval \([a, b]\), then there exists at least one point \(c\) in the interval where \([a, b]\) such that \(f(c)\) equals the average value of \(f\) on \([a, b]\). This is mathematically expressed as: \[ f(c) = \frac{1}{b-a} \int_a^b f(x) \, dx \]
02
Set up the Integral
For the function \(f(x) = x^2\) on the interval \([-1, 1]\), we need to compute \[ \int_{-1}^{1} x^2 \, dx \]
03
Calculate the Integral
Compute the integral: \[ \int_{-1}^{1} x^2 \, dx = \left[ \frac{x^3}{3} \right]_{-1}^{1} \]Evaluate it by plugging in the bounds:\[ \frac{1^3}{3} - \frac{(-1)^3}{3} = \frac{1}{3} - \left(-\frac{1}{3}\right) = \frac{2}{3} \]
04
Calculate the Average Value of the Function
The average value of the function on the interval \([-1, 1]\) is\[ \text{Average} = \frac{1}{1 - (-1)} \times \int_{-1}^{1} x^2 \, dx = \frac{1}{2} \times \frac{2}{3} = \frac{1}{3} \]
05
Find All Values of c
According to the theorem, we need to find \(c\) such that \[ f(c) = \frac{1}{3} \]Substitute \(f(c)\):\[ c^2 = \frac{1}{3} \]Solving for \(c\), we get:\[ c = \pm \frac{1}{\sqrt{3}} \] Both these values lie within the interval \([-1, 1]\).
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.
Continuity
Continuity is a crucial concept when applying the Mean Value Theorem (MVT) for Integrals. It assures us that a function behaves nicely, without any break, throughout a given interval. If you visualize a continuous function, you can draw its curve on a graph without lifting your pen. In mathematical terms, a function is continuous on a closed interval \[a, b\] if it is continuous at every point in \[a, b\].
For the Mean Value Theorem to apply, the function must meet this requirement. In the problem provided, \(f(x) = x^2\) is a polynomial. Since all polynomials are continuous everywhere on the real number line, \(f(x)\) is continuous on the interval \([-1, 1]\).
For the Mean Value Theorem to apply, the function must meet this requirement. In the problem provided, \(f(x) = x^2\) is a polynomial. Since all polynomials are continuous everywhere on the real number line, \(f(x)\) is continuous on the interval \([-1, 1]\).
- This means there are no jumps or breaks in the graph of \(f(x)\) from \(x = -1\) to \(x = 1\).
- Ensures that the MVT can be applied to find a value \(c\) within this interval where the function's value equals its average value.
Definite Integral
A definite integral is a fundamental concept in calculus used to find the accumulated area under a curve within a given interval. When you calculate a definite integral, you're summing up infinitely small slices of the area between the curve of a function and the x-axis over a specific range.
For the function \(f(x) = x^2\) on the interval \([-1, 1]\), we calculate the definite integral:\[ \int_{-1}^{1} x^2 \, dx \]
This integral gives us the total area under the curve from \(x = -1\) to \(x = 1\). Solving this, as shown in the steps, yields:\[ \frac{2}{3} \]
For the function \(f(x) = x^2\) on the interval \([-1, 1]\), we calculate the definite integral:\[ \int_{-1}^{1} x^2 \, dx \]
This integral gives us the total area under the curve from \(x = -1\) to \(x = 1\). Solving this, as shown in the steps, yields:\[ \frac{2}{3} \]
- Essential for finding the average value of the function on this interval.
- Involves evaluating an antiderivative and applying the limits of integration.
Average Value of a Function
The average value of a function over an interval gives us a sense of the function's typical behavior between two points. For a function \(f\) continuous on \[a, b\], the average value is given by:\[ \text{Average} = \frac{1}{b-a} \int_a^b f(x) \, dx \]
In essence, this formula calculates the mean height of the curve \(f(x)\) from \(x = a\) to \(x = b\). Applying this to \(f(x) = x^2\) over \([-1, 1]\), we find:\[ \text{Average} = \frac{1}{2} \times \frac{2}{3} = \frac{1}{3} \]
In essence, this formula calculates the mean height of the curve \(f(x)\) from \(x = a\) to \(x = b\). Applying this to \(f(x) = x^2\) over \([-1, 1]\), we find:\[ \text{Average} = \frac{1}{2} \times \frac{2}{3} = \frac{1}{3} \]
- This average value represents a flat line across the interval that encloses the same area under \(f(x)\).
- According to the Mean Value Theorem for Integrals, there are points within the interval where \(f(x)\) matches this height.