Category Archives: Maths

Evaluating Polynomial Functions

Posted on 10/09/2009 by dougaj4

A polynomial function is a function of the form: a + b*x + c*x^2 + d*x^3 … and the derivative (the slope of the line at point x) of this function is given by: b + 2c*x + 3d*x^2 … … Continue reading →

Posted in Excel, Maths, UDFs, VBA | Tagged , , , , | 5 Comments

Continuous beam with varying stiffness

Posted on 23/08/2009 by dougaj4

Previous Splinebeam post One of my aims in developing the splinebeam function is to carry out non-linear analysis of reinforced concrete beams, allowing for the greatly reduced flexural stiffness of reinforced concrete sections after cracking of the concrete.  To that … Continue reading →

Posted in Arrays, Beam Bending, Excel, Finite Element Analysis, Maths, Newton, UDFs, VBA | Tagged , , , , , , , | 3 Comments

Finding Circle Centres in 3D

Posted on 18/08/2009 by dougaj4

In 2 new functions for IP.xls I described two Excel User Defined Functions (UDFs) to find the radius and centre of a circle defined by 3D coordinates for either 3 points on the circumference, or for two tangent points and the … Continue reading →

Posted in Coordinate Geometry, Excel, Maths, Newton, UDFs, VBA | Tagged , , , , , , , , | 5 Comments

Continuous beam with specified end conditions …

Posted on 09/08/2009 by dougaj4

… and/or support displacements. The previous post in this series derived cubic splines with specified end conditions; either a specified curvature or a specified end slope. I have adapted the splinebeam function to allow input of specified end conditions (either a … Continue reading →

Posted in Arrays, Beam Bending, Excel, Finite Element Analysis, Frame Analysis, Maths, Newton, UDFs, VBA | Tagged , , , , , , , | 1 Comment

Using Goal Seek on Multiple Cells

Posted on 25/07/2009 by dougaj4

The Excel “goal seek” function is useful and powerful, but the procedure for using it on multiple cells is painfully slow. The spreadsheet GSeek.xls provides a simple macro to allow Goal Seek to be automatically applied to a range of … Continue reading →

Posted in Excel, Maths, VBA | Tagged , , , | 17 Comments