Questions: Homework14: Problem 10
(1 point) Find all critical values for the function
f(x) = 9 x^3 - 27 x + 5,
and then list them (separated by commas) in the box below.
List of critical numbers:
Transcript text: Homework14: Problem 10
(1 point) Find all critical values for the function
\[
f(x)=9 x^{3}-27 x+5,
\]
and then list them (separated by commas) in the box below.
List of critical numbers: $\square$
Solution
Solution Steps
To find the critical values of the function \( f(x) = 9x^3 - 27x + 5 \), we need to follow these steps:
Compute the first derivative of the function, \( f'(x) \).
Set the first derivative equal to zero and solve for \( x \) to find the critical points.
Verify the solutions by checking the second derivative or using the first derivative test.
Step 1: Find the First Derivative
To find the critical values of the function \( f(x) = 9x^3 - 27x + 5 \), we first compute the first derivative:
\[
f'(x) = 27x^2 - 27
\]
Step 2: Set the First Derivative to Zero
Next, we set the first derivative equal to zero to find the critical points:
\[
27x^2 - 27 = 0
\]
Step 3: Solve for Critical Points
We can simplify the equation:
\[
27(x^2 - 1) = 0 \implies x^2 - 1 = 0
\]
Factoring gives:
\[
(x - 1)(x + 1) = 0
\]
Thus, the solutions are:
\[
x = -1 \quad \text{and} \quad x = 1
\]
Final Answer
The critical values of the function are \(\boxed{-1, 1}\).