Give a parameterization for the portion of the cone x squared plus y squared equals z squared lying in the first octant. This will be equal to r of u comma v where u and v are our parameters, this will be equal to angle bracket u cosine v comma u sine v comma u. With 0 less than u less than infinity and 0 less than or equal to v less than or equal to pi over 2.

Now this makes sense because cosine and sine together dictate a circle, and we have a circle, since it's a cone, we have a circle that begins at a radius of 0 and then the radius increases. So that's why u as a parameter going from 0 to infinity, and then v is a parameter from 0 to pi over 2 because that's the angle component of these functions. Cosine v sine of v.

And that's in the first octant. So we have 0 2 pi over 2. And actually this should be 0 is less than or equal to v is less than pi over 2 because at that point, we might consider we're not in that octant anymore. And so this is a circle at height z equals u is where we're going with.