Disk-Washer Guidelines

Disk-Washer Guidelines - (b) If you are rotating about...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Solving Solids of Revolution using the Disk/Washer Method 1. Draw a picture of the area you are rotating. You may need to find the intersection points of two curves. 2. Draw a picture of the volume 3. Determine disk or washer (i.e. do you have a big ”R” and a little ”r”, or just a big ”R”) 4. Draw lines from the axis of rotation to the farthest and closest curve, representing R and r, respectively. (a) If you are rotating about something parallel to the y-axis your lines will be perpendicular to the y-axis (parallel to the x-axis). i.e. You’ll have a “dy” (b) If you are rotating about something parallel to the x-axis your lines will be perpendicular to the x-axis (parallel to the y-axis). i.e. You’ll have a “dx” 5. Determine R and r if necessary (a) If you are rotating about something parallel to the y-axis R and r need to be in terms of y
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: (b) If you are rotating about something parallel to the x-axis R and r need to be in terms of x 6. Determine your limits of integration. (a) If you are rotating about something parallel to the y-axis your limits will be y-coordinates. (b) If you are rotating about something parallel to the x-axis your limits will be x-coordinates. 7. If you have a disk use (a) b R a R 2 dy if you are rotating about something parallel to the y-axis. (b) b R a R 2 dx if you are rotating about something parallel to the x-axis 8. If you have a washer (a) b R a [ R 2-r 2 ] dy if you are rotating about something parallel to the y-axis. (b) b R a [ R 2-r 2 ] dx if you are rotating about something parallel to the x-axis...
View Full Document

Ask a homework question - tutors are online