KCET2011MathematicsComplex Number
The value of 1+i 3 (1+ 1 i+1 )² is
Options
- A20
- B9
- C5 4
- D4 5
Correct answer
D. 4 5
Step-by-step solution
| 1+i 3 (1+ 1 i+1 )² |= | (1+i 3 )(i+1)² (i+2)² | ( i²=-1 )= | (1+i 3 ) (i²+1+2 i ) (i²+4+4 i ) |= | (1+i 3 ) 2 i (4 i+3) |= | -2 3 +2 i 3+4 i |=2 | (- 3 +i)(3-4 i) (3+4 i)(3-4 i) |=2 | -3 3 +3 i+4 3 i+4 25 |= 2 25 |(4-3 3 )+(3+4 3 ) i|= 2 25 (4-3 3 )²+(3+4 3 )² = 2 25 16+27-24 3 +9+48+24 3 = 2 25 100 = 2 10 25 = 4 5