## harmonic series

What is 1-1+1-1+1-1+...? How infinite sums challenge our notion of arithmetic.

**Robin Wilson**starts off a four part series on Euler with a look at his life and work.

*Plus*about how he uses mathematics to understand music, and how he managed to combine his passions for music and computing to create a successful career.

**C. J. Sangwin**shows us how eighteenth-century mathematician Leonhard Euler solved one of the foremost infinite series problems of his day.

**John Webb**applies some divergent thinking, taking in the weather, traffic flow and card shuffling along the way.