Euler’s identity is an equality found in mathematics that has been compared to a Shakespearean sonnet and described as " the most beautiful equation." It is a special case of a foundational ...

Euler’s formula involves five fundamental constants: 0, 1, i, e, and Pi, and on adding equality, addition and exponentiation, combines them into a seven-symbol word in a mysterious and useful way.

Some are about famous unsolved problems, others are about notable numbers such as zero, π or e, and still others, including Dr Euler's Fabulous Formula by Paul Nahin, are about important equations.

No matter how the globe is triangulated, Euler’s formula holds. Euler’s Gem provides a bridge between geometry and topology. In geometry, lengths and angles are fixed.

A stretch too far, perhaps, but Nahin’s tale of the formula ei π + 1 = 0, which links five of the most important numbers in mathematics, is remarkable.