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I'm having trouble converting this formula from "FUNDAMENTALS OF ASTRONOMY" page 318 (QB43.3.B37 2006) by Dr.Cesare Barbieri, professor of Astronomy at the university of Pauda, Italy. It is not simplified for the Sun/Earth, it is the full formula with data for Gliese 581/581 c. Can someone help?
=(((((0.0000000567051)*(3840^4))/(4*PI()*((0.0613*149597876600)^2))) * ((4*PI()*((0.29*695500000)^2))/(4*PI()*((11162)^2)))*((PI()*((11162)^2)*(1-0.64))))/0.0000000567051)^0.25
-- GabrielVelasquez ( talk) 04:09, 18 September 2008 (UTC)
Both of those formulas are in the book I mentioned, I just had trouble with the second divided terms in the code, thanks. I want the full version because I have seen other scientists use a different formula that looks wrong in comparison, but I know Selsis et al at Gliese 581 c simplifed it to factor out the Luminosity variables (L=4·pi·R^2·a·T^4)and it just looks wrong if you don't have the full version. GabrielVelasquez ( talk) 21:16, 20 September 2008 (UTC)
dates of floods height of each flood 1965.......................... 5.22 1972.......................... 5.14 1993......................... 6.31 1997........................... 6.13
From this information iam required to find the average height of these floods
for a 1 in 10 year event and a 1 in 100 year event
please help thankyou
if you need to email me it <email removed by
Ζρς ι'β'
¡hábleme!> the 0 is a zero —Preceding
unsigned comment added by
124.170.38.135 (
talk) 04:51, 18 September 2008 (UTC)
Is there a word along the lines of "summand", "integrand", "radicand" for the individual "terms" in a union? For example, in , what word describes the role of , , and ? Is "term" acceptable, or is there a niftier word like "unand" or "unitand"? While we're at it, what about intersections? — Bkell ( talk) 05:01, 18 September 2008 (UTC)
In a tesseract, if the cube (3d) serves the function analogous to a 2d surface for a cube, and the plane serves the function analogous to the edge of a cube in 3d, what would be the status of a point(0 dimensional) in regard to four dimensions? It couldn't be the -1st dimension, could it? Leif edling ( talk) 07:03, 18 September 2008 (UTC)
I read this "analogy" perspective:
Cells, Ridges, Edges: The upshot of all this is that in 4D, objects have a much richer structure than in 3D. In 3D, a polyhedron like the cube has vertices, edges, and faces, and fill a 3D volume. The cube is bounded by faces, which are 2D. Every pair of faces meet at an edge, which is 1D, and edges meet at vertices, which are 0D.
In 4D, objects like the hypercube not only has vertices, edges, and faces, but also cells. A 2D boundary is insufficient to bound a 4D object. Instead, 4D objects are bounded by 3D cells. Each pair of cells meet not at edges, but at 2D faces, also called ridges. The ridges themselves meet at edges, and edges meet at vertices.
The point here is that in 4D, 3D volumes play the role analogous to surfaces in 3D, and 2D ridges play the role analogous to edges. Because of this, it is important to visualize 4D objects by thinking in terms of bounding volumes, and not 2D surfaces. A 2D surface only covers the equivalent area of a thin string in 4D! When you see a 2D surface in the projection of a 4D image, you should understand that it is only a ridge, and not a bounding surface.
I got it here: [1]
So, do the above answers signify that a tesseract does not have 2d planes analogous to the edges of 3d cube? (As is said in the last paragraph above) Leif edling ( talk) 15:49, 18 September 2008 (UTC)
What is an isomorphism when it comes to elliptic curves? I have an idea of what it is based on reading about it in two different books, but neither seems very clear to me.
Knapp's book "Elliptic Curves", which I don't have with me so I can't tell you exactly what it says, basically says two elliptic curves are isomorphic if they are related by an admissible change of variables. That's the definition of isomorphic. But, it never says anything about what that means. I assume it means the group structures are the same. But, is that all it means?
The other book I looked at is Dale Husemoller's "Elliptic Curves". Again, I don't have it with me, but I believe one theorem says two elliptic curves are isomorphic if and only if they have the same j-invariant. This is why I am not entirely sure on the isomorphism meaning only group structure. If this is what it means, then since there are an infinite number of j-invariants, there must be an infinite number of elliptic curve groups possible. The problem is Knapp's book doesn't seem very clear on this. It says only that elliptic curves for ranks up to 12 are known but a fact like there are an infinite number of such groups means clearly elliptic curves of much higher rank exist (higher than any given number).
Can any one help me understand this better? Thanks. StatisticsMan ( talk) 13:46, 18 September 2008 (UTC)
, where and ? I do not mean we need to show that Q is a field, but I have seen other "loose" definitions such as and I just thought that having n and m as negative was redundant, since we only need the numerator, m to be in Z.
What are some applications of groups, either to other mathematical structures or to the real world? Other than a little bit of Galois theory and a mention of homology, my textbooks haven't given much indication of what it's for. Black Carrot ( talk) 22:49, 18 September 2008 (UTC)
Topology Expert ( talk) 05:51, 20 September 2008 (UTC)
Mathematics desk | ||
---|---|---|
< September 17 | << Aug | September | Oct >> | September 19 > |
Welcome to the Wikipedia Mathematics Reference Desk Archives |
---|
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages. |
I'm having trouble converting this formula from "FUNDAMENTALS OF ASTRONOMY" page 318 (QB43.3.B37 2006) by Dr.Cesare Barbieri, professor of Astronomy at the university of Pauda, Italy. It is not simplified for the Sun/Earth, it is the full formula with data for Gliese 581/581 c. Can someone help?
=(((((0.0000000567051)*(3840^4))/(4*PI()*((0.0613*149597876600)^2))) * ((4*PI()*((0.29*695500000)^2))/(4*PI()*((11162)^2)))*((PI()*((11162)^2)*(1-0.64))))/0.0000000567051)^0.25
-- GabrielVelasquez ( talk) 04:09, 18 September 2008 (UTC)
Both of those formulas are in the book I mentioned, I just had trouble with the second divided terms in the code, thanks. I want the full version because I have seen other scientists use a different formula that looks wrong in comparison, but I know Selsis et al at Gliese 581 c simplifed it to factor out the Luminosity variables (L=4·pi·R^2·a·T^4)and it just looks wrong if you don't have the full version. GabrielVelasquez ( talk) 21:16, 20 September 2008 (UTC)
dates of floods height of each flood 1965.......................... 5.22 1972.......................... 5.14 1993......................... 6.31 1997........................... 6.13
From this information iam required to find the average height of these floods
for a 1 in 10 year event and a 1 in 100 year event
please help thankyou
if you need to email me it <email removed by
Ζρς ι'β'
¡hábleme!> the 0 is a zero —Preceding
unsigned comment added by
124.170.38.135 (
talk) 04:51, 18 September 2008 (UTC)
Is there a word along the lines of "summand", "integrand", "radicand" for the individual "terms" in a union? For example, in , what word describes the role of , , and ? Is "term" acceptable, or is there a niftier word like "unand" or "unitand"? While we're at it, what about intersections? — Bkell ( talk) 05:01, 18 September 2008 (UTC)
In a tesseract, if the cube (3d) serves the function analogous to a 2d surface for a cube, and the plane serves the function analogous to the edge of a cube in 3d, what would be the status of a point(0 dimensional) in regard to four dimensions? It couldn't be the -1st dimension, could it? Leif edling ( talk) 07:03, 18 September 2008 (UTC)
I read this "analogy" perspective:
Cells, Ridges, Edges: The upshot of all this is that in 4D, objects have a much richer structure than in 3D. In 3D, a polyhedron like the cube has vertices, edges, and faces, and fill a 3D volume. The cube is bounded by faces, which are 2D. Every pair of faces meet at an edge, which is 1D, and edges meet at vertices, which are 0D.
In 4D, objects like the hypercube not only has vertices, edges, and faces, but also cells. A 2D boundary is insufficient to bound a 4D object. Instead, 4D objects are bounded by 3D cells. Each pair of cells meet not at edges, but at 2D faces, also called ridges. The ridges themselves meet at edges, and edges meet at vertices.
The point here is that in 4D, 3D volumes play the role analogous to surfaces in 3D, and 2D ridges play the role analogous to edges. Because of this, it is important to visualize 4D objects by thinking in terms of bounding volumes, and not 2D surfaces. A 2D surface only covers the equivalent area of a thin string in 4D! When you see a 2D surface in the projection of a 4D image, you should understand that it is only a ridge, and not a bounding surface.
I got it here: [1]
So, do the above answers signify that a tesseract does not have 2d planes analogous to the edges of 3d cube? (As is said in the last paragraph above) Leif edling ( talk) 15:49, 18 September 2008 (UTC)
What is an isomorphism when it comes to elliptic curves? I have an idea of what it is based on reading about it in two different books, but neither seems very clear to me.
Knapp's book "Elliptic Curves", which I don't have with me so I can't tell you exactly what it says, basically says two elliptic curves are isomorphic if they are related by an admissible change of variables. That's the definition of isomorphic. But, it never says anything about what that means. I assume it means the group structures are the same. But, is that all it means?
The other book I looked at is Dale Husemoller's "Elliptic Curves". Again, I don't have it with me, but I believe one theorem says two elliptic curves are isomorphic if and only if they have the same j-invariant. This is why I am not entirely sure on the isomorphism meaning only group structure. If this is what it means, then since there are an infinite number of j-invariants, there must be an infinite number of elliptic curve groups possible. The problem is Knapp's book doesn't seem very clear on this. It says only that elliptic curves for ranks up to 12 are known but a fact like there are an infinite number of such groups means clearly elliptic curves of much higher rank exist (higher than any given number).
Can any one help me understand this better? Thanks. StatisticsMan ( talk) 13:46, 18 September 2008 (UTC)
, where and ? I do not mean we need to show that Q is a field, but I have seen other "loose" definitions such as and I just thought that having n and m as negative was redundant, since we only need the numerator, m to be in Z.
What are some applications of groups, either to other mathematical structures or to the real world? Other than a little bit of Galois theory and a mention of homology, my textbooks haven't given much indication of what it's for. Black Carrot ( talk) 22:49, 18 September 2008 (UTC)
Topology Expert ( talk) 05:51, 20 September 2008 (UTC)