Calculate Area: Finding Ascending Regions of f(x) = -4x² - 24

Question

Find the ascending area of the function

f(x)=4x224 f(x)=-4x^2-24

Video Solution

Solution Steps

00:00 Find the domain of increase of the function
00:03 Notice the coefficient of X squared is negative, so the function is concave down
00:15 Let's examine the trinomial coefficients
00:19 Use the formula to find the vertex of the parabola
00:24 Substitute appropriate values according to the given data and solve for the vertex
00:28 This is the X value at the vertex of the parabola
00:33 Determine when the parabola increases and decreases based on its type
00:37 Draw the X-axis and find the domain of increase
00:50 And this is the solution to the question

Step-by-Step Solution

To solve this problem, the focus is on determining the increasing intervals of the function f(x)=4x224 f(x) = -4x^2 - 24 .

Here's how we'll proceed:

  • Step 1: Differentiate the function.
  • Step 2: Set the derivative greater than 0 to determine the intervals where the function ascends.
  • Step 3: Analyze the results to determine the intervals of increase.

Step 1: Find the derivative of f(x)=4x224 f(x) = -4x^2 - 24 .
The derivative is a straightforward calculation:
f(x)=ddx(4x224)=8x f'(x) = \frac{d}{dx}(-4x^2 - 24) = -8x .

Step 2: Solve f(x)>0 f'(x) > 0 to find the increasing interval.
8x>0 -8x > 0 leads to x<0 x < 0 .

Step 3: Conclude by analyzing this result.
This tells us that the function is increasing when x<0 x < 0 , meaning the ascending area of f(x) f(x) lies in this interval.

Therefore, the solution to this problem is x<0 x < 0 .

Answer

x < 0