Math Problem Statement

Find the average rate of change of ​f(x)equalsnegative 2 x squared plus 2 over each of the following intervals. ​(a) From 0 to 2 ​(b) From 2 to 4 ​(c) From 3 to 6

Solution

To find the average rate of change of a function f(x)f(x) over a given interval [a,b][a, b], you can use the formula:

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

Given the function f(x)=2x2+2f(x) = -2x^2 + 2, let's apply this to each interval.


(a) From 0 to 2:

  1. Evaluate f(0)f(0): f(0)=2(0)2+2=2f(0) = -2(0)^2 + 2 = 2

  2. Evaluate f(2)f(2): f(2)=2(2)2+2=2(4)+2=8+2=6f(2) = -2(2)^2 + 2 = -2(4) + 2 = -8 + 2 = -6

  3. Compute the average rate of change: Average Rate of Change=f(2)f(0)20=622=82=4\text{Average Rate of Change} = \frac{f(2) - f(0)}{2 - 0} = \frac{-6 - 2}{2} = \frac{-8}{2} = -4


(b) From 2 to 4:

  1. Evaluate f(2)f(2) (already done): f(2)=6f(2) = -6

  2. Evaluate f(4)f(4): f(4)=2(4)2+2=2(16)+2=32+2=30f(4) = -2(4)^2 + 2 = -2(16) + 2 = -32 + 2 = -30

  3. Compute the average rate of change: Average Rate of Change=f(4)f(2)42=30(6)2=30+62=242=12\text{Average Rate of Change} = \frac{f(4) - f(2)}{4 - 2} = \frac{-30 - (-6)}{2} = \frac{-30 + 6}{2} = \frac{-24}{2} = -12


(c) From 3 to 6:

  1. Evaluate f(3)f(3): f(3)=2(3)2+2=2(9)+2=18+2=16f(3) = -2(3)^2 + 2 = -2(9) + 2 = -18 + 2 = -16

  2. Evaluate f(6)f(6): f(6)=2(6)2+2=2(36)+2=72+2=70f(6) = -2(6)^2 + 2 = -2(36) + 2 = -72 + 2 = -70

  3. Compute the average rate of change: Average Rate of Change=f(6)f(3)63=70(16)3=70+163=543=18\text{Average Rate of Change} = \frac{f(6) - f(3)}{6 - 3} = \frac{-70 - (-16)}{3} = \frac{-70 + 16}{3} = \frac{-54}{3} = -18


Summary of results:

  • (a) From 0 to 2: 4-4
  • (b) From 2 to 4: 12-12
  • (c) From 3 to 6: 18-18

Would you like any further details or explanations?


Here are some related questions:

  1. How does the average rate of change compare to the instantaneous rate of change?
  2. What is the significance of a negative average rate of change?
  3. Can you find the rate of change over a smaller interval, such as from x=1x = 1 to x=1.5x = 1.5?
  4. How does the shape of the graph of f(x)=2x2+2f(x) = -2x^2 + 2 affect the rate of change?
  5. What happens to the rate of change as xx increases?

Tip: The average rate of change of a quadratic function over an interval can give you an idea of how steeply the curve rises or falls between two points.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Functions
Rate of Change

Formulas

Average Rate of Change = (f(b) - f(a)) / (b - a)
Quadratic Function: f(x) = ax^2 + bx + c

Theorems

None specific to this problem, but quadratic properties and rate of change concepts are applied.

Suitable Grade Level

Grades 9-12