Category Archives: Maths

Displaying trend line equations on line charts

Posted on 16/04/2017 by dougaj4

This post is prompted by a recent comment at Using LINEST for non-linear curve fitting which found that the trend line formula displayed on a chart was totally different from that found using the Linest function. The problem was caused by using a … Continue reading →

Posted in Charts, Charts, Excel, Maths | Tagged , , , | Leave a comment

Weighted Least Squares Regression, using Excel, VBA, Alglib and Python

Posted on 05/02/2017 by dougaj4

Least squares linear regression in Excel is easy.  That’s what the Linest and Trend functions do.  That is, they find the coefficients of a straight line (or higher dimension shape) so that the sum of the squares of the distances of … Continue reading →

Posted in AlgLib, Curve fitting, Excel, Link to Python, Maths, Newton, NumPy and SciPy, UDFs, VBA | Tagged , , , , , , | 9 Comments

On the probability of frog croaks.

Posted on 02/01/2017 by dougaj4

A recent logical puzzle from TED discussed the probability of one of two frogs being female, if we know that at least one of them is male: This puzzle is discussed (arriving at different conclusions) here: and puzzles of this … Continue reading →

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

Brent’s Method and a daft engineer’s blog

Posted on 23/12/2016 by dougaj4

Browsing links on Brent’s Method I found: Daft Engineer – Numerical Methods and Excel* which is well worth a look (plenty of stuff on statistics and Python, with the odd dash of Excel).  The link has VBA code for a … Continue reading →

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

Nearest Lookup Function

Posted on 21/10/2016 by dougaj4

The Excel Lookup functions (including VLookup, HLookup and Match) all allow for an “exact” or “closest” match on numerical data, but the closest option has a number of problems: The data must be sorted For VLookup and HLookup the data … Continue reading →

Posted in Coordinate Geometry, Excel, Maths, UDFs, VBA | Tagged , , , , , , , , | 2 Comments