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Topic: [ap-calculus] another problem
Replies: 7   Last Post: May 3, 2011 5:09 PM

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Jason Waller

Posts: 140
Registered: 12/2/10
re:[ap-calculus] another problem
Posted: May 3, 2011 11:44 AM
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The diameter of the semi-circles, drawn from the x-axis to the line, will have a length equal to the y-value of the line, -.5x+4. Thus the radius of each semi-circle is -.25x+2. The area of each semi-circle is then .5pi(-.25x+2)^2.

The line has an x-intercept of (8,0), so integrate .5pi(-.25x+2)^2 from 0 to 8 to get approx 16.755.

HTH,
Jason Waller
Helix Charter HS
San Diego, CA

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The base of a solid is a region in 1st quadrant bounded by x-axis, y-axis and the line x+2y=8. Cross-sections of the solid perpendicular to the x-axis are semi-circles, what is the volume of the solid. Answer is 16.755--I keep getting a much bigger answer. Any help???

Mark A Wise JBHS Mercersburg, PA
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Course related websites:
http://apcentral.collegeboard.com/calculusab
http://apcentral.collegeboard.com/calculusbc
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