Numeri complessi

Question

[attach]26205[/attach] ma perché -1?

StefanoPescetto · Accepted Answer

@yuki [attach]26211[/attach] (I)² = - 1 cos (2a) = cos² (a) - sin² (a)   Quindi: cos²(pi/3) - sin²(pi/3) = cos(2*pi/3)

exProf · Answer

* z1 = 1*(cos(π/3) + i*sin(π/3))* (z1)^2 = (1^2)*(cos(2*π/3) + i*sin(2*π/3)) = (- 1 + i*√3)/2* z2 = 1*(cos(4*π/3) + i*sin(4*π/3)) = (- 1 - i*√3)/2* (z1)^2 + z2 = (- 1 + i*√3)/2 + (- 1 - i*√3)/2 = (- 2)/2 = - 1

Numeri complessi

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