For the function f(x) = 2x^3 - 9x^2 + 12x, find the local maxima.

Practice Questions

Q1
For the function f(x) = 2x^3 - 9x^2 + 12x, find the local maxima.
  1. (1, 5)
  2. (2, 0)
  3. (3, 0)
  4. (0, 0)

Questions & Step-by-Step Solutions

For the function f(x) = 2x^3 - 9x^2 + 12x, find the local maxima.
  • Step 1: Start with the function f(x) = 2x^3 - 9x^2 + 12x.
  • Step 2: Find the derivative of the function, which is f'(x). The derivative tells us the slope of the function.
  • Step 3: Calculate the derivative: f'(x) = 6x^2 - 18x + 12.
  • Step 4: Set the derivative equal to zero to find critical points: 6x^2 - 18x + 12 = 0.
  • Step 5: Simplify the equation by dividing everything by 6: x^2 - 3x + 2 = 0.
  • Step 6: Factor the quadratic equation: (x - 1)(x - 2) = 0.
  • Step 7: Solve for x: This gives us x = 1 and x = 2 as critical points.
  • Step 8: To determine if these points are local maxima, we need to evaluate the function at these points: f(1) and f(2).
  • Step 9: Calculate f(1): f(1) = 2(1)^3 - 9(1)^2 + 12(1) = 2 - 9 + 12 = 5.
  • Step 10: Calculate f(2): f(2) = 2(2)^3 - 9(2)^2 + 12(2) = 16 - 36 + 24 = 4.
  • Step 11: Compare the values: f(1) = 5 and f(2) = 4. Since f(1) is greater than f(2), x = 1 is a local maximum.
  • Finding Local Maxima – This involves taking the derivative of a function, setting it to zero to find critical points, and using the second derivative test or evaluating the function at those points to determine if they are local maxima or minima.
  • Critical Points – Critical points are found where the first derivative is zero or undefined, which are candidates for local maxima or minima.
  • Second Derivative Test – This test helps confirm whether a critical point is a local maximum, local minimum, or neither by evaluating the second derivative at that point.
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