Chapter 5: Integration and Its Applications 5.7 Volumes of Solids of Revolution
Solid of Revolution Formed by revolving a plane region about a line The line is the axis of revolution
The Disc Method The volume of the solid formed by revolving the region bounded by the graph f and the x-axis (a ≤ x ≤ b) about the x-axis
The Disc Method
Example 1 Find the volume of the solid formed by revolving the region bounded by the graph of f(x) = -x2 + x and the x-axis about the x-axis.
The Washer Method Volume of a solid of revolution with a hole Used with two functions If revolved around the x-axis, we can use the Disc Method and subtract the results f(x) is the outer radius and g(x) is the inner radius
The Washer Method
Example 2 Find the volume of the solid formed by revolving the region bounded by the graphs about the the x-axis
Example 3 A regulation-size football can be modeled as a solid of revolution formed by revolving the graph of About the x-axis. Use this model to find the volume of a football.
Homework P. 372 1-24