Calculus activity 4 (revolve f(x) = -x^2 + 9, 0 <= x <= 3, about y = 2)

[armn91]

I uploaded two pictures. Please, see my screenshot of what I have been able to do so far. Hopefully, someone can help me out.

Thank you!

 

[blamocur]

Do you remember the area of a circle formula?

 

[Steven G]

You can't find what the radius is until you draw the graph.

 

[Dr.Peterson]

Please, see my screenshot of what I have been able to do so far. Hopefully, someone can help me out.

Surely you can plot a graph of y = -x^2 + 9. That's essentially all you have left to do. Perhaps you're misreading what they are asking.

Part of that will be to find where y = -x^2 + 9 intersects y = 2.

Then you can think about whether your limits of integration are okay.

You'll have to make a small correction to your formula, but I think you have the radius essentially right, so most of your work is good. What are you not sure of, besides making the graph?

You can't find what the radius is until you dray the graph.

I try not to dray my graphs. It's much easier to draw them.