Author Archives: dougaj4

Elegant proofs 2 – The area of a circle

Posted on 02/07/2008 by dougaj4

We are so familiar with the formula for the area enclosed by a circle that we tend not to think much about how it was derived, at least I don’t. The proofs of the formula are in fact many and … Continue reading →

Posted in Maths, Newton | Tagged , , , , | 4 Comments

Pythagoras, Penrose and Pov-Ray

Posted on 30/06/2008 by dougaj4

Images based on Pythagorean tiling, Penrose tiling, and projections onto the Riemann Sphere by PM2ring, a regular contributor to the ABC Self-Service Science Forum (words by the artist):  Various renderings of a Pythagorean tiling. Mostly using the 3,4,5 triangle. This … Continue reading →

Posted in Maths, Newton | Tagged , , , , | 3 Comments

Importing text files with VBA – 3

Posted on 27/06/2008 by dougaj4

The text import file has been modified to split large files into one or more ranges. The maximum number of rows for each range is specified, together with a sufficient number of valid range names, which may be on the … Continue reading →

Posted in Excel, UDFs | Tagged , , , , , | 20 Comments

Irish Graffiti

Posted on 25/06/2008 by dougaj4

On the 16th October 1843 the Irish mathematician William Hamilton was taking a walk with his wife, alongside the Royal Canal in Dublin, when the answer to a problem that he had been puzzling over came to him, and he … Continue reading →

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

Drawing in Excel – 2

Posted on 22/06/2008 by dougaj4

Before getting down to basics, the attached file: Animation demo Illustrates how Excel shapes can be simply animated. Screen shot: The code for the animation (having previously drawn a circle and a rectangle with no fill, and noted their names): … Continue reading →

Posted in Drawing, Excel, Newton | Tagged , , , , | 19 Comments