Math Problem Statement

how to Find the average rate of change of the​ function

Solution

The average rate of change of a function f(x)f(x) over an interval [a,b][a, b] is calculated using the formula:

Average Rate of Change=f(b)f(a)ba\text{Average Rate of Change} = \frac{f(b) - f(a)}{b - a}

Steps to Calculate:

  1. Identify the interval [a,b][a, b].

    • aa: The starting xx-value of the interval.
    • bb: The ending xx-value of the interval.
  2. Find the function values at x=ax = a and x=bx = b.

    • f(a)f(a): Substitute aa into the function f(x)f(x).
    • f(b)f(b): Substitute bb into the function f(x)f(x).
  3. Apply the formula: Substitute f(a)f(a), f(b)f(b), aa, and bb into the formula and simplify.

Example:

Suppose the function is f(x)=3x2+2xf(x) = 3x^2 + 2x, and you want the average rate of change over the interval [1,3][1, 3].

  1. a=1a = 1, b=3b = 3.
  2. Find f(1)f(1) and f(3)f(3): f(1)=3(1)2+2(1)=3+2=5f(1) = 3(1)^2 + 2(1) = 3 + 2 = 5 f(3)=3(3)2+2(3)=27+6=33f(3) = 3(3)^2 + 2(3) = 27 + 6 = 33
  3. Apply the formula: Average Rate of Change=f(3)f(1)31=3352=282=14\text{Average Rate of Change} = \frac{f(3) - f(1)}{3 - 1} = \frac{33 - 5}{2} = \frac{28}{2} = 14

Thus, the average rate of change is 1414.


Do you want to work through a specific function or interval? Let me know!
Here are some related questions to explore further:

  1. What is the significance of the average rate of change in real-world contexts?
  2. How does the average rate of change relate to the slope of a line?
  3. Can you find the instantaneous rate of change using a similar approach?
  4. What happens to the average rate of change as the interval shrinks to a single point?
  5. How does the formula change for different types of functions, like logarithmic or exponential?

Tip: Always plot the function to visualize the change over the interval!

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Math Problem Analysis

Mathematical Concepts

Calculus
Average Rate of Change
Functions

Formulas

Average Rate of Change = (f(b) - f(a)) / (b - a)

Theorems

Slope Formula

Suitable Grade Level

Grades 9-12