Math Problem Statement

Given the function f, of, x, equals, start fraction, 3, x, cubed, divided by, 2, x, cubed, plus, 1, end fraction, commaf(x)= 2x 3 +1 3x 3

​ , find f, prime, of, xf ′ (x) in simplified form.

Solution

The function is given as:

f(x)=3x32x3+1f(x) = \frac{3x^3}{2x^3 + 1}

To find the derivative, f(x)f'(x), we'll use the quotient rule, which is:

ddx(u(x)v(x))=u(x)v(x)u(x)v(x)(v(x))2\frac{d}{dx}\left( \frac{u(x)}{v(x)} \right) = \frac{u'(x)v(x) - u(x)v'(x)}{(v(x))^2}

Step 1: Identify u(x)u(x) and v(x)v(x)

  • u(x)=3x3u(x) = 3x^3
  • v(x)=2x3+1v(x) = 2x^3 + 1

Step 2: Find the derivatives u(x)u'(x) and v(x)v'(x)

  • u(x)=ddx(3x3)=9x2u'(x) = \frac{d}{dx}(3x^3) = 9x^2
  • v(x)=ddx(2x3+1)=6x2v'(x) = \frac{d}{dx}(2x^3 + 1) = 6x^2

Step 3: Apply the quotient rule

Now, applying the quotient rule:

f(x)=(9x2)(2x3+1)(3x3)(6x2)(2x3+1)2f'(x) = \frac{(9x^2)(2x^3 + 1) - (3x^3)(6x^2)}{(2x^3 + 1)^2}

Step 4: Simplify the numerator

Expand the terms in the numerator:

f(x)=9x2(2x3+1)18x5(2x3+1)2f'(x) = \frac{9x^2(2x^3 + 1) - 18x^5}{(2x^3 + 1)^2}

Distribute the 9x29x^2 in the first term:

f(x)=18x5+9x218x5(2x3+1)2f'(x) = \frac{18x^5 + 9x^2 - 18x^5}{(2x^3 + 1)^2}

The 18x518x^5 terms cancel out, leaving:

f(x)=9x2(2x3+1)2f'(x) = \frac{9x^2}{(2x^3 + 1)^2}

Thus, the derivative in simplified form is:

f(x)=9x2(2x3+1)2f'(x) = \frac{9x^2}{(2x^3 + 1)^2}

Would you like a detailed explanation of any step, or to clarify any part of the process?

Here are 5 related questions to practice:

  1. What is the derivative of x43x2+2\frac{x^4}{3x^2 + 2}?
  2. How do you apply the quotient rule when the numerator is a constant?
  3. What happens to the derivative when both numerator and denominator have the same degree?
  4. Can the chain rule be applied to solve this function instead of the quotient rule?
  5. How does the quotient rule apply when both terms are linear?

Tip: Always simplify the numerator and denominator before applying the quotient rule to make calculations easier!

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Calculus
Derivatives
Quotient Rule

Formulas

Quotient Rule: d/dx [u(x)/v(x)] = [u'(x)v(x) - u(x)v'(x)] / [v(x)]^2
Power Rule: d/dx [x^n] = n*x^(n-1)

Theorems

Quotient Rule
Simplification of Rational Expressions

Suitable Grade Level

Grades 11-12 or College-level Calculus