[tex]Z^{2} +4=0[/tex]
Δ[tex]= b^{2} -4ac=0-4*1*4=-16[/tex]
[tex]z_{1} = \frac{-b-i \sqrt{(-delta)} }{2a} = \frac{0-i \sqrt{16} }{2} = \frac{-4i}{2} =-2i[/tex]
[tex]z_{1} = \frac{-b+i \sqrt{(-delta)} }{2a} = \frac{0+i \sqrt{16} }{2} = \frac{4i}{2} =2i[/tex]
S={-2i: 2i}
