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If z is any complex number and Given: iz3+z2−z+i=0, where i=−1,\text{Given: } iz^3 + z^2 - z + i = 0, \text{ where } i = \sqrt{-1}
Question

If z is any complex number and Given: iz3+z2z+i=0, where i=1,\text{Given: } iz^3 + z^2 - z + i = 0, \text{ where } i = \sqrt{-1}, \quad then what is the value of Find: (z+1)2\text{Find: } (|z| + 1)^2 ?

A.

1

B.

4

C.

81

D.

121

Correct option is B

Given: iz3+z2z+i=0, where i=1,\text{Given: } iz^3 + z^2 - z + i = 0, \text{ where } i = \sqrt{-1}, \quad

Solution:

iz3+z2z+i=0iz2(zi)1(zi)=0(iz21)(zi)=0z2=1i,(z=i)z=1(z+1)2=(1+1)2=4\begin{aligned}&iz^3 + z^2 - z + i = 0 \\&iz^2(z - i) - 1(z - i) = 0 \\&(iz^2 - 1)(z - i) = 0 \\&z^2 = \frac{1}{i}, \quad (z = i) \\&|z| = 1 \\&(|z| + 1)^2 = (1 + 1)^2 = 4\end{aligned}

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