find the absolute maximum and minimum values of each function over the indicated interval, and indicate the…

find the absolute maximum and minimum values of each function over the indicated interval, and indicate the x - values at which they occur. f(x)=3x^4 - 2x^3,-3,3

find the absolute maximum and minimum values of each function over the indicated interval, and indicate the x - values at which they occur. f(x)=3x^4 - 2x^3,-3,3

Answer

Explanation:

Step1: Find the derivative

Differentiate $f(x)=3x^{4}-2x^{3}$ using the power - rule. The power rule states that if $y = x^{n}$, then $y^\prime=nx^{n - 1}$. $f^\prime(x)=12x^{3}-6x^{2}=6x^{2}(2x - 1)$

Step2: Find the critical points

Set $f^\prime(x)=0$. $6x^{2}(2x - 1)=0$ $6x^{2}=0$ gives $x = 0$ and $2x-1=0$ gives $x=\frac{1}{2}$. These are the critical points.

Step3: Evaluate the function at critical points and endpoints

Evaluate $f(x)$ at $x=-3,x = 0,x=\frac{1}{2},x = 3$.

  • When $x=-3$: $f(-3)=3(-3)^{4}-2(-3)^{3}=3\times81+2\times27=243 + 54=297$
  • When $x = 0$: $f(0)=3(0)^{4}-2(0)^{3}=0$
  • When $x=\frac{1}{2}$: $f(\frac{1}{2})=3(\frac{1}{2})^{4}-2(\frac{1}{2})^{3}=3\times\frac{1}{16}-2\times\frac{1}{8}=\frac{3}{16}-\frac{1}{4}=\frac{3 - 4}{16}=-\frac{1}{16}$
  • When $x = 3$: $f(3)=3(3)^{4}-2(3)^{3}=3\times81-2\times27=243-54 = 189$

Answer:

The absolute maximum value is $297$ and it occurs at $x=-3$. The absolute minimum value is $-\frac{1}{16}$ and it occurs at $x=\frac{1}{2}$.