What is the origin of 'sleep tight'?
Read moreOne of the mysteries of the English language finally explained.
A theorem which states that (cos θ + i sin θ)ⁿ = cos nθ + i sin nθ, where i is the square root of −1.
Early 18th century: named after Abraham de Moivre (1667–1754), French-born mathematician, fellow of the Royal Society.