Math Problem Statement

Consider the function g ( x )

13 x 2 + 6 x − 5

A) What is the average rate of change of g from 14 to 20 ? B) What is the average rate of change of g from 16 to 20 ?

Solution

We are given the function g(x)=13x2+6x5g(x) = 13x^2 + 6x - 5. To find the average rate of change of this function over an interval, we use the formula:

Average Rate of Change=g(b)g(a)ba\text{Average Rate of Change} = \frac{g(b) - g(a)}{b - a} where aa and bb are the endpoints of the interval.

A) Average rate of change from 14 to 20:

Here, a=14a = 14 and b=20b = 20.

  1. First, calculate g(14)g(14): g(14)=13(14)2+6(14)5=13(196)+845=2548+845=2627g(14) = 13(14)^2 + 6(14) - 5 = 13(196) + 84 - 5 = 2548 + 84 - 5 = 2627

  2. Next, calculate g(20)g(20): g(20)=13(20)2+6(20)5=13(400)+1205=5200+1205=5315g(20) = 13(20)^2 + 6(20) - 5 = 13(400) + 120 - 5 = 5200 + 120 - 5 = 5315

  3. Now, apply the formula for the average rate of change: g(20)g(14)2014=531526276=26886=448\frac{g(20) - g(14)}{20 - 14} = \frac{5315 - 2627}{6} = \frac{2688}{6} = 448

Thus, the average rate of change from 14 to 20 is 448.

B) Average rate of change from 16 to 20:

Here, a=16a = 16 and b=20b = 20.

  1. First, calculate g(16)g(16): g(16)=13(16)2+6(16)5=13(256)+965=3328+965=3419g(16) = 13(16)^2 + 6(16) - 5 = 13(256) + 96 - 5 = 3328 + 96 - 5 = 3419

  2. Use the previously calculated g(20)=5315g(20) = 5315.

  3. Now, apply the formula for the average rate of change: g(20)g(16)2016=531534194=18964=474\frac{g(20) - g(16)}{20 - 16} = \frac{5315 - 3419}{4} = \frac{1896}{4} = 474

Thus, the average rate of change from 16 to 20 is 474.

Do you want more details or have any questions?

Here are 5 related questions to expand on this:

  1. How do you interpret the significance of average rate of change in real-world applications?
  2. What would the instantaneous rate of change of g(x)g(x) be at x=14x = 14?
  3. How does the average rate of change differ from the derivative of a function?
  4. How would the average rate of change change if the interval was from 10 to 14 instead?
  5. How do you calculate the rate of change for non-polynomial functions?

Tip: The average rate of change is closely related to the slope of the secant line between two points on a curve.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Functions
Average Rate of Change

Formulas

Average Rate of Change = (g(b) - g(a)) / (b - a)
Quadratic function g(x) = ax^2 + bx + c

Theorems

Secant Line Slope Theorem

Suitable Grade Level

Grades 10-12