Category Archives: Maths

Spherical Geometry and Vincenty’s Formulae

Posted on 27/09/2020 by dougaj4

Wikipedia has detailed articles on: Spherical Geometry  and Vincenty’s Formulae (for geometric calculations on an ellipsoid). The spreadsheet Vincenty.zip uses those resources to perform the following calculations, using both on-sheet calculations and VBA user-defined functions (UDF’s): Calculation of distance and … Continue reading →

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

Section Properties for Rotated Shapes

Posted on 06/08/2020 by dougaj4

I have just posted an update to my section properties spreadsheet, last discussed at: Using Section Properties- Group The new version can be downloaded from: Section Properties07-Group.zip The main sheet provides section properties for a wide variety of defined shapes: This … Continue reading →

Posted in Beam Bending, Coordinate Geometry, Excel, Frame Analysis, Maths, Newton, UDFs, VBA | Tagged , , , , | Leave a comment

Numerical integration with on-sheet calculations

Posted on 08/07/2020 by dougaj4

Following a comment here I have prepared a spreadsheet that works through the Tanh-Sinh Quadrature process with on-sheet calculations.  For that purpose Graeme Dennes has provided a simplified version of the code: QUAD_RODRIGUEZ_TANH_SINH for finite intervals. Translated from HP RPN … Continue reading →

Posted in Excel, Maths, Newton, Numerical integration, UDFs, VBA | Tagged , , , , , | 10 Comments

LinEstGap with non-linear functions

Posted on 14/03/2020 by dougaj4

The LinEstGap user defined function (UDF) allows the built-in Linest function to be used on data with empty cells or hidden rows, returning results that agree with the chart trend-line function, which automatically ignores blank cells and hidden data.  It … Continue reading →

Posted in Arrays, Curve fitting, Excel, Maths, Newton, UDFs, VBA | Tagged , , , , , , , , , | 4 Comments

Katherine Johnson, NASA Legend

Posted on 26/02/2020 by dougaj4

Cartoon by Steve Breen from The San-Diego Union Tribune. More on Katherine Johnson.

Posted in Maths, Newton | Tagged , , | Leave a comment