MHT CET202122 Sep 2021Evening ShiftMathematicsComplex NumberActual
If is the complex cube root of unity, the (3+5 +3 ^2 )^2+ (3+3 +5 ^2 )^2=
Options
- A-1
- B0
- C4
- D-4
Correct answer
D. -4
Step-by-step solution
aligned & (3+5 +3 ^2 )^2+ (3+3 +5 ^2 )^2 & = (3+3 +3 ^2+2 )^2+ (3+3 +3 ^2+2 ^2 )^2 & = [3 (1+ + ^2 )+2 ]^2+ [3 (1+ + ^2 )+2 ^2 ]^2 & =(3(0)+2 )^2+ [3(0)+2 ^2 ]^2=4 ^2+4 ^4 & =4 ^2 (1+ ^2 )=4 ^2(- ) & =-4 ^2=-4 aligned