If f(x) = x^4 - 4x^3, what is f'(2)? (2019)

Practice Questions

Q1
If f(x) = x^4 - 4x^3, what is f'(2)? (2019)
  1. 0
  2. 8
  3. 16
  4. 12

Questions & Step-by-Step Solutions

If f(x) = x^4 - 4x^3, what is f'(2)? (2019)
  • Step 1: Identify the function f(x) = x^4 - 4x^3.
  • Step 2: Find the derivative of f(x), which is f'(x). To do this, use the power rule: for x^n, the derivative is n*x^(n-1).
  • Step 3: Apply the power rule to each term in f(x):
  • - For x^4, the derivative is 4*x^(4-1) = 4x^3.
  • - For -4x^3, the derivative is -4*3*x^(3-1) = -12x^2.
  • Step 4: Combine the derivatives to get f'(x) = 4x^3 - 12x^2.
  • Step 5: Now, we need to find f'(2). Substitute x = 2 into the derivative f'(x).
  • Step 6: Calculate f'(2) = 4(2^3) - 12(2^2).
  • Step 7: Calculate 2^3 = 8, so 4(2^3) = 4*8 = 32.
  • Step 8: Calculate 2^2 = 4, so 12(2^2) = 12*4 = 48.
  • Step 9: Now, subtract: 32 - 48 = -16.
  • Step 10: Therefore, f'(2) = -16.
  • Differentiation – The process of finding the derivative of a function, which represents the rate of change of the function with respect to its variable.
  • Polynomial Functions – Understanding the behavior and properties of polynomial functions, including their derivatives.
  • Evaluation of Derivatives – Calculating the value of the derivative at a specific point.
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