We recently started working on solving washer and disks equations and I really enjoy this subject. I have always been more of a visual learner, and when constructing the integrals for making 3D shapes, it just makes sense to me. You always find the area of the flat shape created by the multiple lines. Then for disks you square f(x) and multiple it by pie, and with washers you You multiply by pie and the width.
Disks:
Disks:
Washers: (Substitute the equations for R^2 - r^2)
This has been a good unit for me probably because it makes a lot of sense. At the end of the day you are just plugging in the proper number/equations to find a volume. It's like plugging in a side length then finding the volume of a cube, only on steroids. I can't wait to see what we do with this next!