Last modified on 11 March 2011, at 13:14

Trigonometry/e to the i Pi

Take the formula

ei θ = cos θ + i sin θ.

If θ = π radians, cos θ = -1 and sin θ = 0 so the formula becomes

ei π = -1

or

ei π + 1 = 0,

a formula relating five key numbers in mathematics.