How do I use the Disk Formula (Calculus) if I move the x-axis of rotation up or down?

Question

Example:

1st f(x)= 9-x^2

x-axis is at y=5

Assume the interval [-2,2]

* I mean instead of V= pi § (9-x^2)^2 - 25 dx, could I rewrite it differently? Since my function is now 5 units closer to the x-axis now that it is at the y= 5 line?

Answer 1

If you have a TI-83 Plus or TI-89 there are some good programs that will help with this.

Try this:

http://www.calculatorti.com/ti-programs/ti-83-plus-ti-84-plus/calculus/functions-shell-method-disk-method-integration-washer-method-area-centroid-and-more.php

Hopefully that helps.

Answer 2

 this is not a answer but please talk to me im new on here!