Category Archives: Maths

3D Intersections

Posted on 19/03/2011 by dougaj4

Following a discussion at the Eng-Tips Forum, I have written an Excel User Defined Function (UDF) to find the intersection point of two 3D line segments.  The UDF has been added to the IP2 spreadsheet, which is available for free … Continue reading →

Posted in Coordinate Geometry, Excel, Maths, Newton, UDFs, VBA | Tagged , , , , | 7 Comments

XNumbers and Tropical Events

Posted on 10/03/2011 by dougaj4

My on-line friend Al Vachris recently sent me a link to the Tropical Events site, which features a detailed analysis of the orbital motion of the Earth and the other bodies of the solar system, all done in Excel, and … Continue reading →

Posted in Excel, Maths, Newton, Numerical integration | Tagged , , , | 16 Comments

Double Exponential Quadrature

Posted on 07/03/2011 by dougaj4

Graeme Dennes has updated his Tanh-Sinh Quadrature spreadsheet to include Double Exponential Quadrature.  His brief notes are given below, and more details and links to background information are included in the download file. ================================================================= Double Exponential Quadrature UDFs added to Tanh-Sinh Quadrature … Continue reading →

Posted in Excel, Maths, Newton, Numerical integration, UDFs, VBA | Tagged , , , , , | 1 Comment

Non linear regression – 2; ALGLIB functions

Posted on 05/03/2011 by dougaj4

The previous post looked at using the Excel Solver to fit a non-linear equation to a given set of data, using the least squares method.  This approach is reasonably convenient and straightforward, but it has a number of disadvantages: The … Continue reading →

Posted in AlgLib, Concrete, Excel, Maths, Newton, UDFs, VBA | Tagged , , , , , | 8 Comments

Non linear regression – 1

Posted on 01/03/2011 by dougaj4

Recent posts have described how to fit linear equations (or equations that can be made linear) to a set of data, using the Excel Linest functions, or User Defined Functions (UDF’s) linking to the ALGLIB library (see Using LINEST for non-linear … Continue reading →

Posted in AlgLib, Concrete, Excel, Maths, Newton | Tagged , , , | 6 Comments