若w=-2/(1+根号3i),则1+w+w^2等于
3个回答

w=-2/(1+根号3i)

=-2(1-根号3i)/[(1+根号3i)(1-根号3i)]

=-2(1-根号3i)/[1²-(根号3i)²]

=-2(1-根号3i)/[1-(-3)]

=-2(1-根号3i)/[1+3]

=-2(1-根号3i)/4

=-(1-根号3i)/2

=(根号3i-1)/2

w^2=(根号3i-1)²/4

=[(根号3i)²-2根号3i+1]/4

=[(-3)-2根号3i+1]/4

=[-2-2根号3i]/4

=-(1+根号3i)/2

1+w+w^2

=1+(根号3i-1)/2+[-(1+根号3i)/2]

=1+(根号3i-1-1-根号3i)/2

=1+(-1-1)/2

=1-1

=0