Questions: Learning Outcome O5: Problem 5
(1 point)
Directions: Use the function f(x) below to answer the following questions.
f(x) = x^4 - 50 x^2 - 7
Find the x-values(s) where f has a relative maximum / relative minimum.
1. Relative Maximum(s):
2. Relative Minimum(s):
Transcript text: Learning Outcome O5: Problem 5
(1 point)
Directions: Use the function $f(x)$ below to answer the following questions.
\[
f(x)=x^{4}-50 x^{2}-7
\]
Find the $x$-values(s) where $f$ has a relative maximum / relative minimum.
1. Relative Maximum(s): $\square$
2. Relative Minimum(s): $\square$
Solution
Solution Steps
To find the relative maximum and minimum of the function \( f(x) = x^4 - 50x^2 - 7 \), we need to follow these steps:
Find the derivative: Compute the first derivative of the function, \( f'(x) \), to find the critical points.
Solve for critical points: Set \( f'(x) = 0 \) and solve for \( x \) to find the critical points.
Determine the nature of critical points: Use the second derivative test by computing \( f''(x) \). Evaluate \( f''(x) \) at each critical point to determine if it is a relative maximum or minimum.
Step 1: Find the First Derivative
The function is given by \( f(x) = x^4 - 50x^2 - 7 \). We compute the first derivative:
\[
f'(x) = 4x^3 - 100x
\]
Step 2: Solve for Critical Points
To find the critical points, we set the first derivative equal to zero:
\[
4x^3 - 100x = 0
\]
Factoring out \( 4x \), we have:
\[
4x(x^2 - 25) = 0
\]
This gives us the critical points:
\[
x = -5, \quad x = 0, \quad x = 5
\]
Step 3: Determine the Nature of Critical Points
Next, we compute the second derivative:
\[
f''(x) = 12x^2 - 100
\]
We evaluate the second derivative at each critical point: