| [ Total Views: 1128 | Total Replies: 7 | Thread Id: 19013 ] |
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 BiX
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| posted on February 15th, 2004 at 02:16 PM |
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long shot- excel guru's
Ok iam trying to get a spreadsheet developed for work ( use it for extra credit for post grad work at uni ).
I have to get out r ^(2/3) (ie r to the 2/3rds power) out of an equation (eg reverse it out). Now i have the function of xroot of a number on my
calculator but can't find the same function in excel. any ideas?
wes u developed some good spreadsheets, any ideas? |
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Brad
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| posted on February 15th, 2004 at 02:21 PM |
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mmm
YOu need to talk to WES ... he is an Excell Guru ....
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 vanderaj
A.k.a.: Andrew van der Stock
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| posted on February 15th, 2004 at 02:24 PM |
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y = r ^ ( 2/3 )
y = exp(2/3* ln(r))
That might help if you can reverse that. The mathematica pages for roots are very pretty:
Square root:
http://mathworld.wolfram.com/SquareRoot.html
Inverse functions:
http://mathworld.wolfram.com/InverseFunction.html
Andrew
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BiX
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| posted on February 15th, 2004 at 02:32 PM |
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andrew thats what iam trying to reverse
the equation is (mannings equation)
Qy= (1/n) * (r^(2/3)) * (Se^(1/2))
I have Qy, n, Se but need to find r,
so r^2/3=Qy/(1/n)/Se^(1/2)
nor need to get rid of the 2/3 power to find r by itself
Iam sick of doing 3 pages of calcs to find the required channel size for a discharge point of a catchment then having to do it over again when when
one of the planners wants to change the layout of the site!!!!
so developing a spread sheet to make it easier and mabye the scientist can use it to. |
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modulus
A.k.a.: Peter Hill
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| posted on February 15th, 2004 at 02:37 PM |
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r^(2/3) = x
therefore
x = r^(3/2)
hth
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vanderaj
A.k.a.: Andrew van der Stock
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| posted on February 15th, 2004 at 03:12 PM |
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Don't you mean
x = r^(2/3)
r = x^(3/2)
?
Andrew
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modulus
A.k.a.: Peter Hill
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| posted on February 15th, 2004 at 03:16 PM |
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^^^ What he said...
Yes, that's what i meant.
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BiX
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| posted on February 15th, 2004 at 03:53 PM |
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:thumb:thumb:thumb:thumb:thumb:thumb:thumb
thanks guys should have thought about the math way not the write formula for excel. |
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vw54
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| posted on February 15th, 2004 at 05:46 PM |
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Hey LETS try n keep Excel simple...
I know how to do most things but lets keep it simple please
Now access is a different matter
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Baja Wes
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| posted on February 16th, 2004 at 08:37 AM |
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I didn't reply to this yesterday as I was out riding my motorbike on a ride day for 10.5 hours. I'm a bit sore now.
Yes I could've helped, and yes I'm pretty familiar with Excel.
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