Math Problem Statement

for the equation f(x)=3x2+2x-5 find the average rate of change of f on [x,x+h]

Solution

To find the average rate of change of the function f(x)=3x2+2x5f(x) = 3x^2 + 2x - 5 on the interval [x,x+h][x, x+h], we use the formula:

Average Rate of Change=f(x+h)f(x)h\text{Average Rate of Change} = \frac{f(x+h) - f(x)}{h}

  1. First, calculate f(x+h)f(x+h). Substitute x+hx+h into the function:

f(x+h)=3(x+h)2+2(x+h)5f(x+h) = 3(x+h)^2 + 2(x+h) - 5

Expand this expression:

f(x+h)=3(x2+2xh+h2)+2(x+h)5f(x+h) = 3(x^2 + 2xh + h^2) + 2(x+h) - 5 =3x2+6xh+3h2+2x+2h5= 3x^2 + 6xh + 3h^2 + 2x + 2h - 5

  1. Now, subtract f(x)f(x) from f(x+h)f(x+h):

f(x+h)f(x)=(3x2+6xh+3h2+2x+2h5)(3x2+2x5)f(x+h) - f(x) = (3x^2 + 6xh + 3h^2 + 2x + 2h - 5) - (3x^2 + 2x - 5) =6xh+3h2+2h= 6xh + 3h^2 + 2h

  1. Finally, divide the result by hh:

f(x+h)f(x)h=6xh+3h2+2hh\frac{f(x+h) - f(x)}{h} = \frac{6xh + 3h^2 + 2h}{h} =6x+3h+2= 6x + 3h + 2

Thus, the average rate of change of f(x)f(x) on the interval [x,x+h][x, x+h] is:

6x+3h+26x + 3h + 2

Would you like more details or have any questions? Here are 5 related questions:

  1. How do you interpret the average rate of change geometrically?
  2. What is the significance of the term 3h3h as h0h \to 0?
  3. How does this expression simplify when h0h \to 0, representing the instantaneous rate of change?
  4. Can you apply the same method to find the average rate of change for a linear function?
  5. What are the steps to compute the derivative of f(x)f(x) using the limit definition?

Tip: The average rate of change is the slope of the secant line between two points on the function.

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Math Problem Analysis

Mathematical Concepts

Calculus
Average Rate of Change
Quadratic Functions

Formulas

Average Rate of Change = (f(x+h) - f(x)) / h

Theorems

None explicitly required; relies on basic calculus concepts

Suitable Grade Level

Grades 10-12