⁴√-1

√-1=i lub -i (jednostka urojona)

⁴√-1= 1

⁴√-1 = ⁴√1(cos((π+2kπ)/4) + i*sin((π+2kπ)/4)), k∈{0, 1, 2, 3} ⁴√-1 = cos(π/4) + i*sin(π/4) = √2/2 + i(√2/2) ∨ ⁴√-1 = cos(3π/4) + i*sin(3π/4) = -√2/2 + i(√2/2) ∨ ⁴√-1 = cos(5π/4) + i*sin(5π/4) = -√2/2 - i(√2/2) ∨ ⁴√-1 = cos(7π/4) + i*sin(7π/4) = √2/2 - i(√2/2)