NDA2024MathematicsComplex NumberActual
If 1 is a cube root of unity, then what is (1+ - ^2 )¹⁰⁰+ (1- + ^2 )¹⁰⁰ equal to?
Options
- A2¹⁰⁰ ^2
- B2¹⁰⁰
- C2¹⁰⁰
- D-2¹⁰⁰
Correct answer
D. -2¹⁰⁰
Step-by-step solution
aligned & Let I= (1+ - ^2 )¹⁰⁰+ (1- + ^2 )¹⁰⁰ & = (- ^2- ^2 )¹⁰⁰+(- - )¹⁰⁰ 1+ + ^2=0 & =2¹⁰⁰ ( ²⁰⁰+ ¹⁰⁰ ) & =2¹⁰⁰ ( ^2+ ) ^3=1 & =-2¹⁰⁰ . aligned