Locate the absolute extrema of the function on the closed interval

f(x) = 2(3-x) [-1,2]

drwls drwls answered
14 years ago

6 - 2x is a straight line with a negative slope. In the interval [-1,2], it is highest when x is smallest (-1) and lowest when x is highest (2).


You don't need to use calculus to answer this question.

Anonymous Anonymous answered
14 years ago

drwls is right no need for calculus here but if youd like to use it

f(x)=2(3-x) [-1,2]
f'(x)=-2
no critical values therefore only test endpoints
f(-1)=8 <--- abs. max (-1,8)
f(2)=2 <---- abs. min (2,2)

Step-by-Step Bot Step-by-Step Bot answered
8 months ago

To locate the absolute extrema of the function f(x) = 2(3-x) on the closed interval [-1,2], follow the steps below:

1. Find the critical points of the function:
To find the critical points, set the derivative of f(x) equal to zero and solve for x.
f'(x) = -2
Setting f'(x) = 0, we get:
-2 = 0
There are no critical points in this case.

2. Evaluate the function at the endpoints of the interval:
- Evaluate f(-1):
f(-1) = 2(3-(-1)) = 2(3+1) = 2*4 = 8
- Evaluate f(2):
f(2) = 2(3-2) = 2(1) = 2

3. Compare the values obtained in step 2 to determine the absolute extrema:
- The maximum value of f(x) = 8 occurs at x = -1.
- The minimum value of f(x) = 2 occurs at x = 2.

Therefore, the absolute maximum value of f(x) = 2(3-x) on the interval [-1,2] is 8, and it occurs at x = -1.
The absolute minimum value of f(x) = 2(3-x) on the interval [-1,2] is 2, and it occurs at x = 2.

Explain Bot Explain Bot answered
8 months ago

To locate the absolute extrema of a function on a closed interval, you need to do the following steps:

Step 1: Find the critical points of the function on the interval.

To do this, you need to find where the derivative of the function is either 0 or does not exist. Let's start by finding the derivative of the given function:

f(x) = 2(3 - x)

To find the derivative, apply the power rule and consider the chain rule:

f'(x) = -2

Since the derivative of the function is constant (-2), it means the function has no critical points on the interval [-1, 2].

Step 2: Evaluate the function at the endpoints of the interval.

Evaluate the function at both -1 and 2 since they are the endpoints of the interval [-1, 2]:

f(-1) = 2(3 - (-1)) = 2(3 + 1) = 2(4) = 8

f(2) = 2(3 - 2) = 2(1) = 2

Step 3: Compare the values obtained in step 2 and identify the absolute maximum and minimum.

From step 2, we got f(-1) = 8 and f(2) = 2.

So, the absolute maximum of the function is 8, which occurs at x = -1 on the given interval [-1, 2]. The absolute minimum of the function is 2, which occurs at x = 2 on the given interval [-1, 2].

Therefore, the absolute maximum is 8, and it occurs at x = -1, while the absolute minimum is 2, and it occurs at x = 2.

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