# Thread: Surface integral over an annulus

1. ## Ackbeet, while we're on this subject

What can you tell me about Diamond Transforms?

2. What can you tell me about Diamond Transforms?
Absolutely nothing. I've never heard of them before. Are they known as something else? Here's a list of transforms. I don't see diamond transforms on there at all. Could you describe them a bit?

3. Originally Posted by Ackbeet
Absolutely nothing. I've never heard of them before. Are they known as something else? Here's a list of transforms. I don't see diamond transforms on there at all. Could you describe them a bit?
Unfortunately when I did a Google search, nothing relevant turned up and this term was used by a poster on a prior thread so I'll consider the matter closed.

4. Originally Posted by wonderboy1953
Since you were never one for numbers, what brings you to a math website?

Since this is the second time (besides this thread) that I haven't gotten an answer to my question leads me to believe that no such formula exists to transform a double integral into a single integral. Can you prove me wrong?
I'm here for the entertainment. Clearly!

Perhaps I didn't use the term "transform" in a strict mathematical sense. I was more refering to the fact that as you compute a multiple integral, it reduces to a single integral, which reduces to some expression.

For example,

If we want the area between $y=x^2$ and $y=x$ from 0 to 1 we can either express it as,

$\int_a^b [ F(x) - G(x) ] dx \to \int_0^1 (x-x^2) dx$

or

$\int_0^1 dx \int_{x^2}^x dy$

Clearly the second reduces to the first representation. It's not a "transformation" persay.

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