If f is a continuous and a is a positive number (think of a as a parameter), show that .

Here, V = {}

{}

{}

Hint: if you are good at visualization, you may be able to "see" that the same region can be written in a **different** way as

V = {}

{}

{}

(I have given you the limits for x.) If you get this right, the rest is easy.

I am horrible at visualization. lol I have a sketch of this. I have that the top is z=a. The back is x=0. A side is x=y, and another side is y=z. I have no idea how to rewrite the region though. I think that it may be since z=a. But I can't figure out the "new" inequality for z. Furthermore, I really don't know how redefining this helps to prove the original statement.