find the absolute maximum and absolute minimum values of the function, if they exist, over the indicated…

find the absolute maximum and absolute minimum values of the function, if they exist, over the indicated interval. when no interval is specified, use the real line (-∞,∞). f(x)=24x - x² a. absolute maximum is 288; no absolute minimum b. no absolute maximum; absolute minimum is 12 c. absolute maximum is 144; no absolute minimum d. there are no absolute extrema.
Answer
Explanation:
Step1: Find the derivative
The derivative of $f(x)=24x - x^{2}$ is $f^\prime(x)=24 - 2x$.
Step2: Set derivative equal to 0
Set $24 - 2x = 0$. Solving for $x$ gives $2x=24$, so $x = 12$.
Step3: Determine if it's a max or min
The second - derivative $f^{\prime\prime}(x)=-2<0$. So $x = 12$ is a local maximum.
Step4: Find the maximum value
Substitute $x = 12$ into $f(x)$: $f(12)=24\times12-12^{2}=288 - 144=144$. Since the function is a parabola opening downwards ($a=-1$ in $y = ax^{2}+bx + c$), as $x\to\pm\infty$, $y\to-\infty$. So there is no absolute minimum.
Answer:
C. Absolute maximum is 144; no absolute minimum