e**(i*a) = cos(a) + i*sin(a)

x + i*y = sqrt(x**2+y**2) * e**(i*atan2(y,x))

Complex numbers have two equivalent representations of polar and cartesian.

(Leonhard Euler)

E = h*f
p = h*l

(Particle-Wave duality, postulate of Quantum Mechanics)