JEE Main20248 Apr 2024Evening ShiftMathematicsComplex NumberActual
The sum of all possible values of [- , 2 ] , for which 1+i 1-2 i is purely imaginary, is equal
Options
- A3
- B2
- C5
- D4
Correct answer
A. 3
Step-by-step solution
aligned & Z= 1+i 1-2 i & Z=- Z 1+i 1-2 i =- ( 1+i 1-2 i ) & (1+i )( 1-2 i )=-(1-2 i )( 1+i ) & (1+i )(1+2 i )=-(1-2 i )(1-i ) & 1+3 i -2 ^2 =- (1-3 i -2 ^2 ) & 2-4 ^2 =0 & ^2 = 1 2 =- 4 ,- 3 4 , 4 , 3 4 , 5 4 , 7 4 & sum =3 aligned