With the method of cylindrical shells we sum up the volumes of thin cylinders.
The volume of a cylinder is
`2pi*r*h*dr,`
where `h` is the height (the value of a function), `r` is the radius of a cylinder (the distance from the axis of rotation to the argument) and `dr` is the thickness.
Here this is `2pi*(x+1)*sqrt(x)dx` and the volume is
`2pi int_0^1 (x+1)sqrt(x) dx=2pi int_0^1 (x^(3/2)+x^(1/2)) dx =`
`=2pi(2/(5)x^(5/2)+2/(3)x^(3/2))_0^1=2pi(2/5+2/3)=32/(15)pi.`
With the method of cylindrical shells we sum up the volumes of thin cylinders.
The volume of a cylinder is
`2pi*r*h*dr,`
where `h` is the height (the value of a function), `r` is the radius of a cylinder (the distance from the axis of rotation to the argument) and `dr` is the thickness.
Here this is `2pi*(x+1)*sqrt(x)dx` and the volume is
`2pi int_0^1 (x+1)sqrt(x) dx=2pi int_0^1 (x^(3/2)+x^(1/2)) dx =`
`=2pi(2/(5)x^(5/2)+2/(3)x^(3/2))_0^1=2pi(2/5+2/3)=32/(15)pi.`
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