Math Problem Statement

Compute the derivative of f(x) = (-3x^3 + 7x +11)(2x^2 -4) using product rule

Solution

To find the derivative of the function f(x)=(3x3+7x+11)(2x24)f(x) = (-3x^3 + 7x + 11)(2x^2 - 4) using the product rule, we proceed as follows:

Product Rule

The product rule states that if f(x)=g(x)h(x)f(x) = g(x) \cdot h(x), then the derivative is: f(x)=g(x)h(x)+g(x)h(x)f'(x) = g'(x)h(x) + g(x)h'(x) Here, g(x)=3x3+7x+11g(x) = -3x^3 + 7x + 11 and h(x)=2x24h(x) = 2x^2 - 4.

Step 1: Differentiate g(x)g(x) and h(x)h(x)

  • g(x)=3x3+7x+11g(x) = -3x^3 + 7x + 11 g(x)=9x2+7g'(x) = -9x^2 + 7
  • h(x)=2x24h(x) = 2x^2 - 4 h(x)=4xh'(x) = 4x

Step 2: Apply the product rule

Using the product rule: f(x)=g(x)h(x)+g(x)h(x)f'(x) = g'(x)h(x) + g(x)h'(x) Substitute the values of g(x)g(x), g(x)g'(x), h(x)h(x), and h(x)h'(x): f(x)=(9x2+7)(2x24)+(3x3+7x+11)(4x)f'(x) = (-9x^2 + 7)(2x^2 - 4) + (-3x^3 + 7x + 11)(4x)

Step 3: Expand both terms

  1. Expand the first term: (9x2+7)(2x24)(-9x^2 + 7)(2x^2 - 4) (9x2)(2x2)+(9x2)(4)+7(2x2)+7(4)=18x4+36x2+14x228=18x4+50x228(-9x^2)(2x^2) + (-9x^2)(-4) + 7(2x^2) + 7(-4) = -18x^4 + 36x^2 + 14x^2 - 28 = -18x^4 + 50x^2 - 28

  2. Expand the second term: (3x3+7x+11)(4x)(-3x^3 + 7x + 11)(4x) (3x3)(4x)+(7x)(4x)+(11)(4x)=12x4+28x2+44x(-3x^3)(4x) + (7x)(4x) + (11)(4x) = -12x^4 + 28x^2 + 44x

Step 4: Combine all terms

Now combine the two results: f(x)=(18x4+50x228)+(12x4+28x2+44x)f'(x) = (-18x^4 + 50x^2 - 28) + (-12x^4 + 28x^2 + 44x) f(x)=18x412x4+50x2+28x2+44x28f'(x) = -18x^4 - 12x^4 + 50x^2 + 28x^2 + 44x - 28 f(x)=30x4+78x2+44x28f'(x) = -30x^4 + 78x^2 + 44x - 28

Thus, the derivative of the function is: f(x)=30x4+78x2+44x28f'(x) = -30x^4 + 78x^2 + 44x - 28

Would you like further details or explanations on any step?


Here are 5 related questions:

  1. How does the chain rule differ from the product rule?
  2. What is the derivative of a product of three functions?
  3. How would the derivative change if the function had a quotient?
  4. Can you apply the product rule to trigonometric functions?
  5. How do you find second derivatives using the product rule?

Tip: Always simplify the expressions before differentiating to make the process easier!

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Calculus
Derivatives
Product Rule

Formulas

Product rule: f'(x) = g'(x)h(x) + g(x)h'(x)
Power rule: d/dx[x^n] = nx^(n-1)

Theorems

Product Rule of Differentiation

Suitable Grade Level

Grades 11-12 / College Calculus