Math Problem Statement

Find f'(x) two ways: (1) using the quotient rule and (2) simplifying first. f(x) = (x^6 + 4) / x^6. Which of the following shows the result of using the quotient rule?

Solution

Let's break down and solve the problem step-by-step.

Function provided:

f(x)=x6+4x6f(x) = \frac{x^6 + 4}{x^6}

Task:

  1. Find f(x)f'(x) using the quotient rule.
  2. Simplify the function first, then find f(x)f'(x).

Step 1: Using the Quotient Rule

The quotient rule for derivatives is: (uv)=vuuvv2\left( \frac{u}{v} \right)' = \frac{v \cdot u' - u \cdot v'}{v^2} where u=x6+4u = x^6 + 4 and v=x6v = x^6.

  • Derivative of uu: u=6x5u' = 6x^5
  • Derivative of vv: v=6x5v' = 6x^5

Applying the quotient rule: f(x)=x66x5(x6+4)6x5(x6)2f'(x) = \frac{x^6 \cdot 6x^5 - (x^6 + 4) \cdot 6x^5}{(x^6)^2}

Now, let's simplify this expression.

Step 2: Simplify the Function First

Simplify f(x)f(x): f(x)=x6+4x6=1+4x6f(x) = \frac{x^6 + 4}{x^6} = 1 + \frac{4}{x^6}

Now, find the derivative of f(x)=1+4x6f(x) = 1 + 4x^{-6}: f(x)=024x7=24x7f'(x) = 0 - 24x^{-7} = -\frac{24}{x^7}

Matching with the Options:

From the options provided, B correctly represents the quotient rule application: f(x)=(x6)(x6+4)(x6+4)(x6)(x6)2f'(x) = \frac{(x^6) \cdot (x^6 + 4)' - (x^6 + 4) \cdot (x^6)'}{(x^6)^2}

Finally, the simplified function is: f(x)=1+4x6f(x) = 1 + \frac{4}{x^6}

Let me know if you would like further details on any of these steps, or have more questions. Here are 5 relative questions for practice:

  1. How do you differentiate functions with exponents?
  2. What are some common mistakes when applying the quotient rule?
  3. Can you explain when it's better to simplify a function before differentiating?
  4. What is the product rule and how is it different from the quotient rule?
  5. How can you verify the result of a derivative calculation?

Tip: Always check if a function can be simplified before applying the quotient rule. This often makes the differentiation easier.

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Math Problem Analysis

Mathematical Concepts

Derivatives
Quotient Rule
Simplification of Rational Functions

Formulas

Quotient Rule: (u/v)' = (v * u' - u * v') / v^2

Theorems

Quotient Rule for Derivatives

Suitable Grade Level

Grades 11-12