I second the motion for Mathcad or SMath. Excel is fine for certain things, and I use it a lot, but engineering calculations like this one really demand a Mathcad/SMath approach. I use both Mathcad and SMath, but I use Mathcad far more often due to my company's software policies. Right now, I only use SMath at home.
With Mathcad/SMath, you get units handling (helpful it you are trying to
not crash a spacecraft into Mars
![[smile] [smile] [smile]](/data/assets/smilies/smile.gif)
), visible equations that are easy to read, much easier root solving, programs, more robust matrix handling, and a bunch of other useful things that Excel doesn't do. Also, understanding an old Mathcad/SMath worksheet that you haven't touched in a while is much easier than with an old Excel spreadsheet. This is especially important if you need to modify the calculation for a new project.
On the other hand, Excel spreadsheets generally require fewer pages than a Mathcad/SMath worksheet and Excel has much better graphing tools, the ability to use conditional formatting, and a bunch of other useful things that Mathcad/SMath don't do. Fortunately, Mathcad (and I think SMath as well) has tools to send data to and from Excel. So, you may want to keep massive data tables in Excel, read the data into a Mathcad worksheet, then export the results to Excel for graphing.
If you have to submit calculations to a client or a reviewing agency (something I do fairly often), they will be able to understand and trust a Mathcad/SMath worksheet, but very likely not the equivalent Excel spreadsheet. The same principle applies to when I mentor/train young engineers. They have a much easier time understanding a calculation by reading a Mathcad/SMath worksheet, even if they aren't Mathcad/SMath users themselves. I am slowly converting my many Excel design spreadsheets to Mathcad, partly for this purpose. In fact, for many routine calculations, I maintain both a Mathcad version and an equivalent Excel version. I usually use the Mathcad version myself and it's what I teach with, but the non-Mathcad users get an Excel spreadsheet to work with, although I always encourage them to create their own tools because that's how they will learn it best.
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"Is it the only lesson of history that mankind is unteachable?"
--Winston S. Churchill