Math Problem Statement

Evaluate and simplify the expression [f(a+h) - f(a)] / h where f(x) = -2x^2 + 3x - 4.

Solution

The problem you're working on asks to evaluate and simplify the expression

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

where f(x)=2x2+3x4f(x) = -2x^2 + 3x - 4.

Step-by-Step Solution:

  1. Find f(a+h)f(a+h): Substituting a+ha+h into f(x)=2x2+3x4f(x) = -2x^2 + 3x - 4, we get:

    f(a+h)=2(a+h)2+3(a+h)4f(a+h) = -2(a+h)^2 + 3(a+h) - 4 Now expand the terms: (a+h)2=a2+2ah+h2(a+h)^2 = a^2 + 2ah + h^2 So: f(a+h)=2(a2+2ah+h2)+3(a+h)4f(a+h) = -2(a^2 + 2ah + h^2) + 3(a + h) - 4 Distribute the terms: f(a+h)=2a24ah2h2+3a+3h4f(a+h) = -2a^2 - 4ah - 2h^2 + 3a + 3h - 4

  2. Find f(a)f(a): Substitute aa into f(x)f(x): f(a)=2a2+3a4f(a) = -2a^2 + 3a - 4

  3. Calculate f(a+h)f(a)f(a+h) - f(a): Now subtract f(a)f(a) from f(a+h)f(a+h): f(a+h)f(a)=(2a24ah2h2+3a+3h4)(2a2+3a4)f(a+h) - f(a) = (-2a^2 - 4ah - 2h^2 + 3a + 3h - 4) - (-2a^2 + 3a - 4) Distribute the negative sign: f(a+h)f(a)=2a24ah2h2+3a+3h4+2a23a+4f(a+h) - f(a) = -2a^2 - 4ah - 2h^2 + 3a + 3h - 4 + 2a^2 - 3a + 4 Combine like terms: f(a+h)f(a)=4ah2h2+3hf(a+h) - f(a) = -4ah - 2h^2 + 3h

  4. Divide by hh: Now divide the expression by hh: f(a+h)f(a)h=4ah2h2+3hh\frac{f(a+h) - f(a)}{h} = \frac{-4ah - 2h^2 + 3h}{h} Simplify each term: 4ahh=4a,2h2h=2h,3hh=3\frac{-4ah}{h} = -4a, \quad \frac{-2h^2}{h} = -2h, \quad \frac{3h}{h} = 3 So the final simplified expression is: f(a+h)f(a)h=4a2h+3\frac{f(a+h) - f(a)}{h} = -4a - 2h + 3

This is the simplified form of the given difference quotient.


Would you like more details on any of these steps, or do you have additional questions?

Here are 5 related questions to explore further:

  1. What is the significance of the difference quotient in calculus?
  2. How would the result change if the function were cubic instead of quadratic?
  3. Can you calculate the limit of this difference quotient as h0h \to 0?
  4. How is the difference quotient related to the derivative of the function?
  5. What happens if you substitute a specific value for aa into the final expression?

Tip: The difference quotient is fundamental in calculus as it leads directly to the definition of the derivative. Understanding how to manipulate and simplify these expressions will be key when you study more advanced topics.

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Functions
Difference Quotient

Formulas

f(x) = -2x^2 + 3x - 4
Difference Quotient: [f(a+h) - f(a)] / h

Theorems

Difference Quotient

Suitable Grade Level

Grades 10-12