Math Problem Statement

What about if f(x) = 1/(x+3)?

Solution

Let's find the difference quotient for the function f(x)=1x+3f(x) = \frac{1}{x+3}.

The difference quotient is given by:

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

1. Calculate f(x+h)f(x+h):

f(x+h)=1(x+h)+3=1x+h+3f(x+h) = \frac{1}{(x+h)+3} = \frac{1}{x+h+3}

2. Find the difference f(x+h)f(x)f(x+h) - f(x):

f(x+h)f(x)=1x+h+31x+3f(x+h) - f(x) = \frac{1}{x+h+3} - \frac{1}{x+3}

To subtract these fractions, we need a common denominator:

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

Simplify the numerator:

f(x+h)f(x)=x+3xh3(x+h+3)(x+3)=h(x+h+3)(x+3)f(x+h) - f(x) = \frac{x + 3 - x - h - 3}{(x+h+3)(x+3)} = \frac{-h}{(x+h+3)(x+3)}

3. Form the difference quotient:

f(x+h)f(x)h=hh(x+h+3)(x+3)\frac{f(x+h) - f(x)}{h} = \frac{-h}{h \cdot (x+h+3)(x+3)}

Simplify by canceling hh in the numerator and denominator:

f(x+h)f(x)h=1(x+h+3)(x+3)\frac{f(x+h) - f(x)}{h} = \frac{-1}{(x+h+3)(x+3)}

So, the difference quotient for f(x)=1x+3f(x) = \frac{1}{x+3} is:

f(x+h)f(x)h=1(x+h+3)(x+3)\frac{f(x+h) - f(x)}{h} = \frac{-1}{(x+h+3)(x+3)}

Would you like further clarification or have any questions?


Here are 5 related questions for further exploration:

  1. How does the difference quotient change as hh approaches 0 for f(x)=1x+3f(x) = \frac{1}{x+3}?
  2. What is the derivative of f(x)=1x+3f(x) = \frac{1}{x+3} using the definition of the derivative?
  3. How would the difference quotient change for a function with a different denominator, such as f(x)=1x+5f(x) = \frac{1}{x+5}?
  4. Can you apply the difference quotient to a function like f(x)=2x+3f(x) = \frac{2}{x+3}?
  5. How does the concept of limits apply to the difference quotient?

Tip: When working with rational functions, always remember to find a common denominator when subtracting fractions. This simplifies the difference quotient and prepares it for taking the limit as hh approaches 0.

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Math Problem Analysis

Mathematical Concepts

Calculus
Difference Quotient
Limits

Formulas

Difference quotient formula

Theorems

Definition of derivative

Suitable Grade Level

Advanced High School