Calculus

[Smartdude613]

Alright so this is my second semester at college. I'm taking Math 132 (Calculus With Anylitical Geometry 2) and am having some trouble understanding this new part in it. I'm hoping someone here could possibly explain it in a way I'd understand.

It's basically finding the area using intergration. Theres the three methods: Disk, Washer, and Shell. Each of these methods seems as confusing as the next. All of them seem easy when they are rotating about the x-axis. It's when there involves movement from that x-axis where y=0 to some other position such as where y=3. Even more complicated to me is when its rotated about the y-axis.

Anyone know what I'm talking about and able to explain it in a way thats somewhat simple to understand?

[jitz]

1 + 1 = a window.

[Aero]

ok, the sick should fit in the shell, after you've inserted it, stick in your headphones and press play.

once finished, throw it all in the washer so it makes it nice and clean for next time.....

.....yeah, i dunno.

[Fozy]

I did this in college, it relates to my higher maths course I did the other year. However, even though I'd find it relatively easy, I'd need to actually be in a class doing it at the time to get into it.

So, any examples?

[Smartdude613]

This example is taken from the quiz I took lastnight which she gave us the answer key for

Use Disk or Washer method. [NO SHELL METHOD]

1) Find the volume of the solid formed by revolving the region bound by the graphs of:

y=e^(2X)

y=0

x=0

x=1

Revolves about the x-axis

Some how I did the problem correct, I just dont understand why it works.

She gave us the equation

V= (pi) * Intergral[ ®^2 dx]

Answer: V= 42.0959 units^3

Answer: V= 13.3995 (pi) units^3

2) Find the volume of the solid formed when the graph of the region bounded by

y=sqrt(16-x^2)

y=1

Revolves about the x-axis

This one for some reason I didn't get, even though it seems like its the same method.

Answer: V= 243.35 units^3

Answer: V= 77.4595 (pi) units^3