Euler's identity

say ('e**i⁢π + 1 ≅ 0 : ', Num.e**Num.pi.i + 1 ≅ 0)
say ('Error: ', Num.e**Num.pi.i + 1)

Output:

e**i⁢π + 1 ≅ 0 : true
Error: -2.42661922624586582047028764157944836122122513308e-58i