1.Disc method.
In this method the volume is given by:
![\boxed{V=\pi\int\limits_a^b\big[f(x)\big]^2}](https://tex.z-dn.net/?f=%5Cboxed%7BV%3D%5Cpi%5Cint%5Climits_a%5Eb%5Cbig%5Bf%28x%29%5Cbig%5D%5E2%7D)
so:
![V=\pi\int\limits_1^3x^4\,dx=\boxed{\pi\int\limits_1^3\big[x^2\big]^2\,dx}](https://tex.z-dn.net/?f=V%3D%5Cpi%5Cint%5Climits_1%5E3x%5E4%5C%2Cdx%3D%5Cboxed%7B%5Cpi%5Cint%5Climits_1%5E3%5Cbig%5Bx%5E2%5Cbig%5D%5E2%5C%2Cdx%7D)
A) Function
over the interval ![[1,3]](https://tex.z-dn.net/?f=%5B1%2C3%5D)
B) We use disk method and f(x) is function of variable x, so we <span>rotate the curve about the x-<span>axis.
2. Shell method.
In this case volume is given by:
</span></span>
So there will be:
A) Function
over the interval
B) We use shell method and f(x) is function of variable x, so we <span>rotate the curve about the y-<span>axis.</span></span>
In this method the volume is given by:
so:
A) Function
B) We use disk method and f(x) is function of variable x, so we <span>rotate the curve about the x-<span>axis.
2. Shell method.
In this case volume is given by:
</span></span>
So there will be:
A) Function
B) We use shell method and f(x) is function of variable x, so we <span>rotate the curve about the y-<span>axis.</span></span>