Find the volume of the solid whose base is the region in the first quadrant bounded by y=x3, y=1, and the y-axis and whose cross-sections perpendicular to the x axis are semicircles.

Respuesta :

For a given [tex]x[/tex] in the interval [0, 1], the corresponding cross-section is a semicircle with diameter [tex]d=1-x^3[/tex], so the area of the cross-section would be [tex]\frac{\pi d^2}8[/tex].

The volume of the solid is then

[tex]\displaystyle\frac\pi8\int_0^1(1-x^3)^2\,\mathrm dx=\boxed{\frac{9\pi}{112}}[/tex]

The volume of a solid is the amount of space in it.

The volume of the solid is: [tex]\mathbf{ \frac{9\pi}{112} }[/tex]

The given parameters are:

[tex]\mathbf{y =x^3,\ \ y=1}[/tex]

From the question, we understand that the cross-sections are semicircles.

This means that, the diameter (d) is:

[tex]\mathbf{d = y_2 -y_1}[/tex]

So, we have:

[tex]\mathbf{d = 1 -x^3}[/tex]

The volume (V) of the solid is then calculated as:

[tex]\mathbf{V = \frac{\pi}{8} \int\limits^a_b {d^2} \, dx }[/tex]

Substitute [tex]\mathbf{d = 1 -x^3}[/tex]

[tex]\mathbf{V = \frac{\pi}{8} \int\limits^1_0 {(1 - x^3)^2} \, dx }[/tex]

Expand

[tex]\mathbf{V = \frac{\pi}{8} \int\limits^1_0 {(1 - 2x^3 + x^6)} \, dx }[/tex]

Integrate, with respect to x

[tex]\mathbf{V = \frac{\pi}{8} {(x - \frac{x^4}{2} + \frac{x^7}{7})} \, |\limits^1_0 }[/tex]

Substitute 1 and 0, for x

[tex]\mathbf{V = \frac{\pi}{8} [(1 - \frac{1^4}{2} + \frac{1^7}{7}) - (0 - \frac{0^4}{2} + \frac{0^7}{7})]}[/tex]

[tex]\mathbf{V = \frac{\pi}{8} [(1 - \frac{1}{2} + \frac{1}{7}) ]}[/tex]

Take LCM

[tex]\mathbf{V = \frac{\pi}{8} [\frac{14 - 7 + 2}{14} ]}[/tex]

[tex]\mathbf{V = \frac{\pi}{8} [\frac{9}{14} ]}[/tex]

Simplify the fraction

[tex]\mathbf{V = \frac{9\pi}{112} }[/tex]

Hence, the volume of the solid is: [tex]\mathbf{ \frac{9\pi}{112} }[/tex]

Read more about volumes at:

https://brainly.com/question/7251133