The investigation offered this month is called Ring on a String,
and uses Excel to optimise a characteristic of interest (minimise a
length in this case).
The ring R is free to run along the taut string AB.
A second string passes through this ring and is pulled tight,
before each end is attached to a peg in the two lines of
Each line of pegs is perpendicular to AB, as shown in the diagram
Using a spreadsheet, determine the position taken by R as the
positions of C and D vary.
You will have to make some decisions about start values for
For example: how long will you make AB, and what different
positions of C and D will you explore?