Math Problem Statement

Find the average rate of change \( \frac{f(x+h) - f(x)}{h} \) for \( f(x) = 4x^2 - 3x + 2 \).

Solution

To solve the problem, we are tasked with finding the average rate of change of f(x)f(x) using the formula:

f(x+h)f(x)h\frac{f(x+h) - f(x)}{h}

where f(x)=4x23x+2f(x) = 4x^2 - 3x + 2. Let’s compute step by step.

Step 1: Find f(x+h)f(x+h)

Substitute x+hx+h into f(x)f(x): f(x+h)=4(x+h)23(x+h)+2f(x+h) = 4(x+h)^2 - 3(x+h) + 2

Expand (x+h)2(x+h)^2: (x+h)2=x2+2xh+h2(x+h)^2 = x^2 + 2xh + h^2 f(x+h)=4(x2+2xh+h2)3(x+h)+2f(x+h) = 4(x^2 + 2xh + h^2) - 3(x + h) + 2 f(x+h)=4x2+8xh+4h23x3h+2f(x+h) = 4x^2 + 8xh + 4h^2 - 3x - 3h + 2

Step 2: Compute f(x+h)f(x)f(x+h) - f(x)

Using f(x)=4x23x+2f(x) = 4x^2 - 3x + 2, subtract f(x)f(x) from f(x+h)f(x+h): f(x+h)f(x)=(4x2+8xh+4h23x3h+2)(4x23x+2)f(x+h) - f(x) = (4x^2 + 8xh + 4h^2 - 3x - 3h + 2) - (4x^2 - 3x + 2)

Simplify: f(x+h)f(x)=8xh+4h23hf(x+h) - f(x) = 8xh + 4h^2 - 3h

Step 3: Divide by hh

The average rate of change is: f(x+h)f(x)h=8xh+4h23hh\frac{f(x+h) - f(x)}{h} = \frac{8xh + 4h^2 - 3h}{h}

Factor hh out from the numerator: f(x+h)f(x)h=h(8x+4h3)h\frac{f(x+h) - f(x)}{h} = \frac{h(8x + 4h - 3)}{h}

Cancel hh (for h0h \neq 0): f(x+h)f(x)h=8x+4h3\frac{f(x+h) - f(x)}{h} = 8x + 4h - 3

Final Answer:

f(x+h)f(x)h=8x+4h3\frac{f(x+h) - f(x)}{h} = 8x + 4h - 3

Would you like me to clarify any steps, or provide further examples or explanations?

Related Questions:

  1. How is the average rate of change formula connected to the derivative?
  2. What happens as h0h \to 0 in this formula?
  3. How do you expand and simplify f(x+h)f(x+h) for polynomial functions in general?
  4. Can this formula be applied to find the slope of the tangent line at a specific point?
  5. How do you interpret the average rate of change geometrically?

Tip:

Always expand (x+h)n(x+h)^n carefully using the binomial theorem or direct multiplication to avoid errors in calculations.

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Math Problem Analysis

Mathematical Concepts

Algebra
Functions
Rate of Change

Formulas

\( \frac{f(x+h) - f(x)}{h} \)
Binomial expansion for \( (x+h)^2 \)

Theorems

Properties of polynomial functions
Simplification of expressions

Suitable Grade Level

Grades 10-12