AP EAMCET201822 Apr 2018Morning ShiftMathematicsComplex NumberActual
If 1, , ^2 are the cube roots of unity, then 1 1+2 + 1 2+ - 1 1+ =
Options
- A1
- B^2
- C0
Correct answer
3
Step-by-step solution
aligned & Given, 1 1+2 + 1 2+ - 1 1+ & = 2+ +1+2 (1+2 )(2+ ) - 1 (1+ ) & = 3+3 (1+2 )(2+ ) - 1 (1+ ) & = (3+3 )(1+ )-(1+2 )(2+ ) (1+2 )(2+ )(1+ ) & = 3+3 +3 +3 ^2- (2+ +4 +2 ^2 ) (1+2 )(2+ )(1+ ) & = 3+6 +3 ^2-2-w-4 -2 ^2 (1+2 )(2+ )(1+ ) & = 1+ + ^2 (1+2 )(2+ )(1+ ) & =0 aligned