Math Problem Statement

Find the ARC of f(x) as Ξ”xβ†’2. Given that f(x)= 3π‘₯

2

-2π‘₯ + 11

Solution

To find the Average Rate of Change (ARC) of f(x)f(x) as Ξ”xβ†’2\Delta x \to 2, given that f(x)=3x2βˆ’2x+11f(x) = 3x^2 - 2x + 11, we can use the formula:

ARC=f(x+Ξ”x)βˆ’f(x)Ξ”x\text{ARC} = \frac{f(x + \Delta x) - f(x)}{\Delta x}

Since we want the ARC specifically as Ξ”xβ†’2\Delta x \to 2, let’s proceed by substituting Ξ”x=2\Delta x = 2 into the formula.

Step 1: Calculate f(x+2)f(x + 2)

  1. Substitute x+2x + 2 into f(x)=3x2βˆ’2x+11f(x) = 3x^2 - 2x + 11: f(x+2)=3(x+2)2βˆ’2(x+2)+11f(x + 2) = 3(x + 2)^2 - 2(x + 2) + 11

  2. Expand (x+2)2(x + 2)^2: (x+2)2=x2+4x+4(x + 2)^2 = x^2 + 4x + 4

  3. Substitute this back into f(x+2)f(x + 2): f(x+2)=3(x2+4x+4)βˆ’2(x+2)+11f(x + 2) = 3(x^2 + 4x + 4) - 2(x + 2) + 11

  4. Distribute and simplify: f(x+2)=3x2+12x+12βˆ’2xβˆ’4+11f(x + 2) = 3x^2 + 12x + 12 - 2x - 4 + 11 f(x+2)=3x2+10x+19f(x + 2) = 3x^2 + 10x + 19

Step 2: Substitute f(x)f(x) and f(x+2)f(x + 2) into the ARC formula

Now we calculate the difference and divide by Ξ”x=2\Delta x = 2: ARC=f(x+2)βˆ’f(x)2=(3x2+10x+19)βˆ’(3x2βˆ’2x+11)2\text{ARC} = \frac{f(x + 2) - f(x)}{2} = \frac{(3x^2 + 10x + 19) - (3x^2 - 2x + 11)}{2}

Step 3: Simplify

  1. Simplify the expression in the numerator: f(x+2)βˆ’f(x)=3x2+10x+19βˆ’3x2+2xβˆ’11f(x + 2) - f(x) = 3x^2 + 10x + 19 - 3x^2 + 2x - 11 =12x+8= 12x + 8

  2. Divide by Ξ”x=2\Delta x = 2: ARC=12x+82=6x+4\text{ARC} = \frac{12x + 8}{2} = 6x + 4

Answer

The Average Rate of Change (ARC) of f(x)=3x2βˆ’2x+11f(x) = 3x^2 - 2x + 11 as Ξ”xβ†’2\Delta x \to 2 is:

6x+4\boxed{6x + 4}

Would you like further clarification, or do you have any questions?


Here are some related questions you might find helpful:

  1. How would we find the instantaneous rate of change of f(x)f(x) instead?
  2. How would changing Ξ”x\Delta x to a different value affect the ARC?
  3. Can we apply the same method if f(x)f(x) was a cubic function?
  4. What is the relationship between ARC and the derivative of f(x)f(x)?
  5. How would the ARC change if f(x)f(x) were linear?

Tip: For quadratic functions, the ARC over any interval approaches the slope of the tangent as the interval narrows.

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Math Problem Analysis

Mathematical Concepts

Average Rate of Change
Quadratic Functions
Algebra

Formulas

ARC = (f(x + Ξ”x) - f(x)) / Ξ”x

Theorems

Rate of Change Theorem

Suitable Grade Level

Grades 10-12