NDA2024MathematicsComplex NumberActual
If 1 is a cube root of unity, then what are the solution of (z-100)^3+1000=0 ?
Options
- A10(1- ), 10 (10- ^2 ), 100
- B10(10- ), 10 (10- ^2 ), 90
- C10(1- ), 10 (10- ^2 ), 1000
- D(1+ ), (10+ ^2 ),-1
Correct answer
B. 10(10- ), 10 (10- ^2 ), 90
Step-by-step solution
aligned & (z-100)^3+1000=0 & (z-100)^3=-1000=(-10)^3 & z-100=-10 & z=90 & z-100=10 w z=100-10 w & z-100=-10 w^2 & z=100-10 w^2 . aligned