Category Archives: UDFs

Cubic Splines

Posted on 02/07/2009 by dougaj4

Cubic splines are used to fit a smooth curve to a series of points with a piecewise series of cubic polynomial curves.  In addition to their use in interpolation, they are of particular interest to engineers because the spline is … Continue reading →

Posted in Beam Bending, Excel, Newton, UDFs, VBA | Tagged , , , , | 73 Comments

A catenary function

Posted on 25/06/2009 by dougaj4

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 … Continue reading →

Posted in Arch structures, Excel, Maths, Newton, UDFs, VBA | 3 Comments

Adding Function Categories and Descriptions

Posted on 21/05/2009 by dougaj4

User defined functions (UDF’s) are by default added to the “User Defined” category in the function list, and when a UDF is selected the words “no help available” appear, rather than a description of the function and it’s parameters.  A rather … Continue reading →

Posted in Excel, UDFs, VBA | Tagged , , , | 3 Comments

Some string functions

Posted on 15/05/2009 by dougaj4

It was pointed out in a comment to this post at Daily Dose of Excel that VBA has a StrReverse function that will (logically enough) reverse a string.  That’s not awfully useful to me (except maybe for Project Euler), but it … Continue reading →

Posted in Excel, UDFs, VBA | Tagged , , , | 5 Comments

Finding square roots …

Posted on 06/05/2009 by dougaj4

… to 100 decimal places. Why would anyone want to do that? To solve Project Euler Problem 80: “It is well known that if the square root of a natural number is not an integer, then it is irrational. The … Continue reading →

Posted in Arrays, Excel, Maths, Newton, UDFs, VBA | 2 Comments