Math Problem Statement

Average Value of a function: The average value of a function f(x) on the interval [a, b] is given by Avg(f) = 1 b − a   b f(x) dx

a .

Find the average value of f(x) =

x2 − 1 x  , 1 ≤ x ≤ 4.

Set up an integral that represents the average value of the function on the given interval.

Solution

The formula for the average value of a function f(x)f(x) on the interval [a,b][a, b] is:

Avg(f)=1baabf(x)dx\text{Avg}(f) = \frac{1}{b - a} \int_{a}^{b} f(x) \, dx

For the function f(x)=x21xf(x) = \frac{x^2 - 1}{x}, on the interval [1,4][1, 4], we can first simplify the function:

f(x)=x21x=x1xf(x) = \frac{x^2 - 1}{x} = x - \frac{1}{x}

Now, applying the formula for the average value, the integral setup becomes:

Avg(f)=14114(x1x)dx\text{Avg}(f) = \frac{1}{4 - 1} \int_{1}^{4} \left( x - \frac{1}{x} \right) dx

Simplifying further:

Avg(f)=1314(x1x)dx\text{Avg}(f) = \frac{1}{3} \int_{1}^{4} \left( x - \frac{1}{x} \right) dx

This is the integral that represents the average value of the function on the interval [1,4][1, 4].

Would you like me to solve the integral next?


5 related questions:

  1. How do you evaluate the integral (x1x)dx\int (x - \frac{1}{x}) dx?
  2. What are the geometric interpretations of the average value of a function?
  3. How do changes in the interval [a,b][a, b] affect the average value of a function?
  4. Can we apply this average value formula to any continuous function?
  5. How does the average value differ for polynomial versus rational functions?

Tip: Always simplify the given function if possible before setting up the integral for the average value.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Calculus
Average Value of a Function
Definite Integral

Formulas

Avg(f) = (1 / (b - a)) ∫[a to b] f(x) dx
f(x) = (x^2 − 1) / x = x − (1 / x)

Theorems

Fundamental Theorem of Calculus

Suitable Grade Level

Grades 11-12