Q. Знайди об'єм тіла, отриманого при обертанні навколо осїабсцис фігури, обмеженої лініями:y=6x2,y=6x
Identify bounds and region: Identify the bounds of integration and the region of interest.The curves intersect where 6x2=6x. Solving for x, we get x2=x, so x(x−1)=0. This gives x=0 and x=1 as points of intersection.
Set up integral for volume: Set up the integral for the volume using the disk method.The volume V is given by the integral from 0 to 1 of π(outer radius2−inner radius2)dx. Here, the outer radius is y=6x (from the line) and the inner radius is y=6x2 (from the parabola).
Express radii and plug in: Express the radii in terms of x and plug into the volume formula.Outer radius = 6x, so outer radius2=36x2.Inner radius = 6x2, so inner radius2=36x4.Volume integral becomes V=π∫01(36x2−36x4)dx.
Simplify and integrate: Simplify and integrate.V=π∫01(36x2−36x4)dx=π∫0136(x2−x4)dx.This simplifies to V=36π∫01(x2−x4)dx.
Calculate final volume: Calculate the integral. ∫01(x2−x4)dx=[3x3−5x5]01=(31−51)−(0−0)=152. V=36π×152=1572π=4.8π.