Let S= \z C : z2+ 6 iz-3=0 \. Then z S z8 is equal to :
- 162
- 184
- 262
- 324
Answer
(1) 162
Solution
z2+ 6 iz-3=0
z= - 6 i ( 6 i )2+122= - 6 i 62
z1= 32 (1-i), z2= 32 (-1-i)
Now (1-i)2=-2i and (-1-i)2=2i
(1-i)8=(-2i)4=16, (-1-i)8=(2i)4=16
z18=z28= ( 32 )4 16=81
z Sz8=81+81=162
Answer: (1)