Math Problem Statement

Evaluate the difference quotient for f left parenthesis x right parenthesis equals 4 x squared minus 3 x plus 5.

Solution

To evaluate the difference quotient for the function f(x)=4x23x+5f(x) = 4x^2 - 3x + 5, we use the formula for the difference quotient:

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

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

Substitute x+hx+h into the function f(x)=4x23x+5f(x) = 4x^2 - 3x + 5:

f(x+h)=4(x+h)23(x+h)+5f(x+h) = 4(x+h)^2 - 3(x+h) + 5

First, expand (x+h)2(x+h)^2:

(x+h)2=x2+2xh+h2(x+h)^2 = x^2 + 2xh + h^2

Now substitute this back into the function:

f(x+h)=4(x2+2xh+h2)3(x+h)+5f(x+h) = 4(x^2 + 2xh + h^2) - 3(x+h) + 5

Expand the terms:

f(x+h)=4x2+8xh+4h23x3h+5f(x+h) = 4x^2 + 8xh + 4h^2 - 3x - 3h + 5

Step 2: Calculate the Difference Quotient

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

f(x+h)f(x)=(4x2+8xh+4h23x3h+5)(4x23x+5)f(x+h) - f(x) = (4x^2 + 8xh + 4h^2 - 3x - 3h + 5) - (4x^2 - 3x + 5)

Simplify the expression:

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

Now, divide the result by hh:

f(x+h)f(x)h=8xh+4h23hh\frac{f(x+h) - f(x)}{h} = \frac{8xh + 4h^2 - 3h}{h}

Simplify by canceling out hh from each term:

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

Final Answer:

The difference quotient is:

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

Do you want more details on this process or have any questions?

Here are 5 related questions for further exploration:

  1. What happens to the difference quotient as hh approaches 0?
  2. How do you interpret the difference quotient geometrically?
  3. How would the difference quotient change if the function had a cubic term?
  4. What is the derivative of f(x)=4x23x+5f(x) = 4x^2 - 3x + 5 using limits?
  5. Can you evaluate the difference quotient for f(x)=x3+2xf(x) = x^3 + 2x?

Tip: The difference quotient is a fundamental concept in calculus, representing the average rate of change of a function over an interval.

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Math Problem Analysis

Mathematical Concepts

Algebra
Calculus
Difference Quotient
Quadratic Functions

Formulas

Difference quotient: (f(x+h) - f(x)) / h
Quadratic expansion: (x+h)^2 = x^2 + 2xh + h^2

Theorems

Difference Quotient Definition
Limit Process for Derivatives

Suitable Grade Level

Grades 11-12