Volumes of Solids of Revolution

[layd33foxx]

Find the volume of the solid generated by revolving the region bounded by the graphs of the equations?

y=22-10x-x<sup>2
y=x+22

about the x-axis & the line y=11</sup>

 

[delgeezee]

Set the Y function equal to each other to find the "intesections" AKA the point at x where the two functions equal to each other touch. You need to do this three times. The intersections will give you your boundaries or interval. For each interval, inegrate the tallest function minus the lower function. You need to integrate for each interval you have and add them together.

 

[tkhunny]

How must we proceed? Pappus' Theorem could be useful. Is that the unit you are on?

 

[layd33foxx]

we haven't discussed pappus the it's just integrating the section is called
[h=2]Volumes of Solids of Revolution[/h]

 

[tkhunny]

Okay. Then let's forget Pappus for a moment. What is your plan for setup?

You'll need points of intersection of the two curves. Do you have those?

You'll need an idea if you are shooting for Shells or Disks (or Washers). What are you thinking is best and why?

Let's see what you get.

 

[layd33foxx]

disk method

 

[tkhunny]

You're not moving in large enough chunks. Are you trying to get me to do your homework? I asked four questions and you answered one of them. You WILL have to do better than that.

Okay, Disks. Now what? Go review the other three questions.