Math Problem Statement

find the average rate of change for f(x)=6x^2+4 on the interval [-1,3]

Solution

Let’s find the average rate of change of f(x)=6x2+4f(x) = 6x^2 + 4 on the interval [1,3][-1, 3].

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

Average rate of change=f(b)f(a)ba\text{Average rate of change} = \frac{f(b) - f(a)}{b - a}

Here:
a=1a = -1 and b=3b = 3.

Step 1: Calculate f(1)f(-1)
f(1)=6(1)2+4=6(1)+4=6+4=10f(-1) = 6(-1)^2 + 4 = 6(1) + 4 = 6 + 4 = 10

Step 2: Calculate f(3)f(3)
f(3)=6(3)2+4=6(9)+4=54+4=58f(3) = 6(3)^2 + 4 = 6(9) + 4 = 54 + 4 = 58

Step 3: Apply the formula
Average rate of change=58103(1)=483+1=484=12\text{Average rate of change} = \frac{58 - 10}{3 - (-1)} = \frac{48}{3 + 1} = \frac{48}{4} = 12

Final Answer:
The average rate of change of f(x)=6x2+4f(x) = 6x^2 + 4 on the interval [1,3][-1, 3] is 12.

Would you like me to explain any step in more detail or explore related ideas?

Here are some related questions:

  1. How is the average rate of change related to the slope of a secant line?
  2. What’s the difference between average rate of change and instantaneous rate of change?
  3. How do we interpret the average rate of change of a quadratic function geometrically?
  4. Can the average rate of change be negative? What would that mean?
  5. How do we find the average rate of change over non-integer intervals?

Tip:
For quadratic functions like this, the average rate of change depends on the shape of the parabola and the interval chosen — so choosing different intervals gives different rates of change!

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Functions
Rate of Change

Formulas

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

Theorems

Concept of Secant Line Slope

Suitable Grade Level

Grades 9-11