Let `i=sqrt(-1)` Define a sequence of complex number by `z_1=0, z_(n+1) = (z_n)^2 + i` for `n>=1`. In the complex plane, how far from the origin is `z
Let `i=sqrt(-1)` Define a sequence of complex number by `z_1=0, z_(n+1) = (z_n)^2 + i` for `n>=1`. In the complex plane, how far from the origin is `z_111`?
A. `1`
B. `2`
C. `3`
D. `4`
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Correct Answer - B
`(b)` `z_(1)=0`, `z_(n+1)=z_(n)^(2)+i`
Put `n=1impliesz_(2)=z_(1)^(2)+i=i`
Put `n=2impliesz_(3)=z_(2)^(2)+i=i^(2)+i=i-1`
Put `n=3impliesz_(4)=z_(3)^(2)+i=(i-1)^(2)+i=-i`
Put `n=4impliesz_(5)=z_(4)^(2)+i=(-i)^(2)+i=i-1`
Put `n=5impliesz_(6)=z_(5)^(2)+i=(i-1)^(2)+i=-i`
Thus `z_(111)=-1+i`
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