Following on from the previous post, here is an Excel User Defined Function (UDF) to calculate the coordinates of any specified catenary, with the option of also finding the tension force at any point.

Download from: Catenary.zip

The download file includes full open source code.  To view the results of the function it must be entered as an array function, i.e.:

1. Enter the function in the top left cell of the output range.
2. Select the entire output range.
3. Press F2
4. Press Ctrl-Shift-Enter

See screen shot below for typical input and output (click on the image for a full size view):

Catenary UDF