Tag Archives: Excel

Using LINEST for non-linear curve fitting

Posted on 19/01/2011 by dougaj4

Update 14 March 2020: See LinEstGap with non-linear functions for the latest version of Linest-Poly with new functions for non-linear curves allowing more convenient input and work with data with gaps errors, and/or hidden lines. Update 28 June 2015:  Also see … Continue reading →

Posted in Charts, Excel, Maths, Newton | Tagged , , , , , | 96 Comments

Evaluating higher order polynomials …

Posted on 17/01/2011 by dougaj4

… and a better solution for quadratics. Having written a better solver for high order polynomials, that raises a few other issues.  The error in the roots found by the RPolyJT was checked by simply substituting each root as the … Continue reading →

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

Solving higher order polynomials

Posted on 13/01/2011 by dougaj4

The Quartic spreadsheet presented here previously (most recently here) uses algebraic techniques to provide an “exact” solution to polynomial equations of up to fouth order.  For polynomials of higher order there is no general algebraic solution, and numerical methods are … Continue reading →

Posted in Excel, Maths, Newton, UDFs, VBA | Tagged , , , , , , | 12 Comments

LatPile update

Posted on 11/01/2011 by dougaj4

I have just posted an update to the LatpilePY spreadsheet, fixing a bug in the way in which it read the first row of data from input PY curves, which was resulting in the program failing to run if there were … Continue reading →

Posted in Concrete, Excel, Geotechnical Engineering, Newton, UDFs, VBA | Tagged , , , , , , | 2 Comments

Elegant Solutions – completing the square

Posted on 08/01/2011 by dougaj4

When I was at school (many years ago), if I recall correctly, we were told of the “completing the square” method of solving quadratic equations, but I never really appreciated the elegance of this method because it was treated as … Continue reading →

Posted in Excel, Maths, Newton | Tagged , , , , | 1 Comment