Comments for Newton Excel Bach, not (just) an Excel Blog
https://newtonexcelbach.com
An Excel blog for engineers and scientists, and an engineering and science blog for Excel users.Mon, 24 Jun 2019 03:32:37 +0000
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Comment on Solving the Lagrangian Point equation for the Moon by dougaj4
https://newtonexcelbach.com/2019/06/23/solving-the-lagrangian-point-equation-for-the-moon/#comment-29482
Mon, 24 Jun 2019 03:32:37 +0000http://newtonexcelbach.com/?p=8717#comment-29482Thanks for letting me know. I have corrected the wording in the spreadsheet example, and added the formula for Point 1. (now uploaded)
Note that when using the QuadbrentT function you just have to update the text formula on the spreadsheet and the solution will automatically update.
When using Goal Seek with the Excel cell formula you first have to update the formula, then run Goal Seek again to adjust the formula result to zero.
For the corrected Goal Seek example for Point 1 I have used the Eval Function to evaluate the text formula. To do that you have to add the cell for the r value to the end of the range listing the known values.
I have left extracting the quintic polynomial coefficients for the Point 1 formula as an exercise for you đź™‚ (but it doesn’t really have any advantage over the QuadbrentT function anyway).

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Comment on Solving the Lagrangian Point equation for the Moon by Robert Williscroft
https://newtonexcelbach.com/2019/06/23/solving-the-lagrangian-point-equation-for-the-moon/#comment-29475
Sun, 23 Jun 2019 19:53:33 +0000http://newtonexcelbach.com/?p=8717#comment-29475This is NOT my best day! I presented an incorrect formula for L1. The correct formula for Lagrange Point 1 (between Earth and Moon) is:
(Me/(R-r)^2)=(Mm/r^2)+(Me/R^2)-r*(Me+Mm)/R^3.
(where Me is Earth mass, Mm is Moon mass. R is Earth-Moon distance, r is distance of L1 from Moon.
(Sorry about that!)

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Comment on Solving the Lagrangian Point equation for the Moon by Robert Williscroft
https://newtonexcelbach.com/2019/06/23/solving-the-lagrangian-point-equation-for-the-moon/#comment-29474
Sun, 23 Jun 2019 19:10:16 +0000http://newtonexcelbach.com/?p=8717#comment-29474Thank you for this information. It turns out that the equation I gave you (and which you used) is for the L2 point (beyond the Moon). The equation for L1 (between earth and Moon) is (Me/(R-r)^2)+(Mm/r^2)-((Me/R^2)+r*(Me+Mm)/R^3).
The same, except the numerator for the first term is (R-r)^2.

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Comment on Fitting high order polynomials by dougaj4
https://newtonexcelbach.com/2011/02/04/fitting-high-order-polynomials/#comment-29471
Sun, 23 Jun 2019 12:47:45 +0000http://newtonexcelbach.wordpress.com/?p=2280#comment-29471See todays post: https://newtonexcelbach.com/2019/06/23/solving-the-lagrangian-point-equation-for-the-moon/
If anything isn’t clear, please ask.

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Comment on Solving Quadratic, Cubic, Quartic and higher order equations; examples by Solving the Lagrangian Point equation for the Moon | Newton Excel Bach, not (just) an Excel Blog
https://newtonexcelbach.com/2014/01/14/solving-quadratic-cubic-quartic-and-higher-order-equations-examples/#comment-29470
Sun, 23 Jun 2019 12:44:47 +0000http://newtonexcelbach.wordpress.com/?p=5313#comment-29470[…] Solving Quadratic, Cubic, Quartic and higher order equations;Â examples […]

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Comment on Iterative solvers and arrays by Solving the Lagrangian Point equation for the Moon | Newton Excel Bach, not (just) an Excel Blog
https://newtonexcelbach.com/2018/10/21/iterative-solvers-and-arrays/#comment-29469
Sun, 23 Jun 2019 12:44:45 +0000http://newtonexcelbach.com/?p=8121#comment-29469[…] Iterative solvers andÂ arrays […]

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Comment on Fitting high order polynomials by Solving the Lagrangian Point equation for the Moon | Newton Excel Bach, not (just) an Excel Blog
https://newtonexcelbach.com/2011/02/04/fitting-high-order-polynomials/#comment-29468
Sun, 23 Jun 2019 12:44:37 +0000http://newtonexcelbach.wordpress.com/?p=2280#comment-29468[…] post was prompted by a recent question at Fitting high orderÂ polynomials, asking for Excel methods to solve the equations for the radius of the Moon’s Lagrangian […]

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Comment on Fitting high order polynomials by Robert Williscroft
https://newtonexcelbach.com/2011/02/04/fitting-high-order-polynomials/#comment-29463
Sat, 22 Jun 2019 18:18:23 +0000http://newtonexcelbach.wordpress.com/?p=2280#comment-29463This quintic equation solves for r=distance from Moon to the Lagrangian Point 1, where Me=Earth mass, Mm=Moon mass, and R=radius of Moon’s orbit.
(Me/(R+r)^2)+(Mm/r^2)=(Me/R^2)+r(Me+Mm)/R^3
Where Me is very much larger than Mm (as here), the equation reduces to an approximate answer of:
r=R*(Mm/3*Me)^1/3
I wish to solve for any values of Me and Mm. Is there an Excel function or method that will accomplish this?

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Comment on Using Section Properties- Group by dougaj4
https://newtonexcelbach.com/2018/06/24/using-section-properties-group/#comment-29393
Wed, 12 Jun 2019 11:34:12 +0000http://newtonexcelbach.com/?p=8003#comment-29393That’s the same as my system. My e-mail address is dougaj4 at gmail.
Could you send a copy of your file as well.
Thanks.

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Comment on Using Section Properties- Group by Mattias
https://newtonexcelbach.com/2018/06/24/using-section-properties-group/#comment-29391
Wed, 12 Jun 2019 05:43:14 +0000http://newtonexcelbach.com/?p=8003#comment-29391Thank you for replying.
I am running version 1,09.
Office 2016 32 bit on win 10 64 bit.
If you want i can send you a printscreen of the issue if you include your email.
Thanks