Math Problem Statement

Find the absolute maximum value and the absolute minimum value, if any, of the function. (If an answer does not exist, enter DNE.) f(x) = x^(2)-x-4 on (0,4)

Solution

To find the absolute maximum and minimum values of the function f(x)=x2x4f(x) = x^2 - x - 4 on the interval [0,4][0, 4], follow these steps:

Step 1: Find the critical points

First, compute the derivative of the function f(x)f(x):

f(x)=ddx(x2x4)=2x1f'(x) = \frac{d}{dx}(x^2 - x - 4) = 2x - 1

Set the derivative equal to zero to find the critical points:

2x1=02x - 1 = 0

Solving for xx:

x=12x = \frac{1}{2}

So, the critical point is x=12x = \frac{1}{2}.

Step 2: Evaluate the function at the critical point and endpoints

Next, evaluate f(x)f(x) at the critical point and the endpoints of the interval, x=0x = 0 and x=4x = 4.

  1. f(0)=(0)2(0)4=4f(0) = (0)^2 - (0) - 4 = -4
  2. f(12)=(12)2124=14124=174f\left(\frac{1}{2}\right) = \left(\frac{1}{2}\right)^2 - \frac{1}{2} - 4 = \frac{1}{4} - \frac{1}{2} - 4 = -\frac{17}{4}
  3. f(4)=(4)2(4)4=1644=8f(4) = (4)^2 - (4) - 4 = 16 - 4 - 4 = 8

Step 3: Identify the absolute maximum and minimum

  • At x=0x = 0, f(0)=4f(0) = -4
  • At x=12x = \frac{1}{2}, f(12)=1744.25f\left(\frac{1}{2}\right) = -\frac{17}{4} \approx -4.25
  • At x=4x = 4, f(4)=8f(4) = 8

Thus, the absolute minimum value is f(12)=174f\left(\frac{1}{2}\right) = -\frac{17}{4}, and the absolute maximum value is f(4)=8f(4) = 8.

Final Answer:

  • Absolute minimum: 174-\frac{17}{4}
  • Absolute maximum: 88

Would you like more details or have any questions?


Here are 5 related questions for further practice:

  1. Find the critical points of the function f(x)=x26x+9f(x) = x^2 - 6x + 9 on the interval [1,5][1, 5].
  2. Determine the absolute maximum and minimum values of f(x)=x33x2+2f(x) = x^3 - 3x^2 + 2 on [0,2][0, 2].
  3. Find the critical points and classify them as minima or maxima for f(x)=2x39x2+12x1f(x) = 2x^3 - 9x^2 + 12x - 1.
  4. Evaluate the absolute extrema of f(x)=sin(x)f(x) = \sin(x) on the interval [0,π][0, \pi].
  5. Solve for the absolute maximum and minimum values of f(x)=ex2f(x) = e^{-x^2} on the interval [2,2][-2, 2].

Tip: Always check both the critical points and the endpoints when determining the absolute extrema of a function on a closed interval.

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Math Problem Analysis

Mathematical Concepts

Calculus
Quadratic Functions
Critical Points
Extrema

Formulas

f'(x) = 2x - 1
f(x) = x^2 - x - 4

Theorems

Extreme Value Theorem

Suitable Grade Level

Grades 11-12