JEE Main20198 Apr 2019Evening ShiftMathematicsComplex NumberActual
If z = 3 2 + i 2 i = - 1 , then 1 + i z + z 5 + i z 8 9 is equal to:
Options
- A- 1
- B1
- C0
- D- 1 + 2 i 9
Correct answer
A. - 1
Step-by-step solution
z = 3 2 + i 2 ∴ i z = - 1 2 + 3 2 i = ω ∴ 1 + i z + z 5 + i z 8 9 = 1 + ω + ω 5 i 5 + i × ω 8 i 8 9 = 1 + ω - i ω 2 + i ω 2 9 = - ω 2 9 = - ω 18 = - 1