question let the region r be the area enclosed by the function f(x)=x² - 2 and g(x)=3x - 2. if the region r…

question let the region r be the area enclosed by the function f(x)=x² - 2 and g(x)=3x - 2. if the region r is the base of a solid such that each cross - section perpendicular to the x - axis is a square, find the volume of the solid. you may use a calculator and round to the nearest thousandth. answer attempt 1 out of 3
Answer
Explanation:
Step1: Find intersection points
Set $f(x)=g(x)$, so $x^{2}-2 = 3x - 2$. Rearranging gives $x^{2}-3x=0$, factoring out $x$ we get $x(x - 3)=0$. The solutions are $x = 0$ and $x=3$.
Step2: Determine side - length of square cross - section
The side - length $s$ of each square cross - section perpendicular to the $x$ - axis is $s=(3x - 2)-(x^{2}-2)=3x - x^{2}$.
Step3: Find the volume formula
The volume $V$ of the solid with square cross - sections is given by the integral $V=\int_{a}^{b}s^{2}dx$, where $a = 0$, $b = 3$ and $s = 3x - x^{2}$. So $V=\int_{0}^{3}(3x - x^{2})^{2}dx$.
Step4: Expand the integrand
Expand $(3x - x^{2})^{2}=(3x - x^{2})(3x - x^{2})=9x^{2}-6x^{3}+x^{4}$.
Step5: Integrate term - by - term
$\int(9x^{2}-6x^{3}+x^{4})dx=9\times\frac{x^{3}}{3}-6\times\frac{x^{4}}{4}+\frac{x^{5}}{5}+C = 3x^{3}-\frac{3}{2}x^{4}+\frac{1}{5}x^{5}+C$.
Step6: Evaluate the definite integral
$V=\left[3x^{3}-\frac{3}{2}x^{4}+\frac{1}{5}x^{5}\right]_{0}^{3}=3\times3^{3}-\frac{3}{2}\times3^{4}+\frac{1}{5}\times3^{5}$. $V = 3\times27-\frac{3}{2}\times81+\frac{1}{5}\times243$. $V = 81-\frac{243}{2}+\frac{243}{5}$. $V=\frac{810 - 1215+486}{10}=\frac{71}{10}=7.125$.
Answer:
$7.125$