If `z_k=cos((kpi)/10)+isin((kpi)/10)`, then `z_1z_2z_3z_4` is equal to

If z_(k)=cos((kpi)/(10))+isin((kpi)/(10)) , then z_(1)z_(2)z_(3)z_(4) is equal to

If z_(k)=cos((k pi)/(10))+i sin((k pi)/(10)), then z_(1)z_(2)z_(3)z_(4) is equal to (A)-1 (B) 2(C)-2 (D) 1

If Z_r=cos((2rpi)/5)+isin((2rpi)/5),r=0,1,2,3,4,... then z_1z_2z_3z_4z_5 is equal to

If z=cos((pi)/(3))-isin((pi)/(3)) then z^(2)-z+1=....

Let z_(k) = cos((2kpi)/(10)) -isin ((2kpi)/(10)), k = 1,2,…..,9

Let z_(k)=cos((2kpi)/(10))+isin((2kpi)/(10)) ,k=1,2,…,9. Then match the column

If Z_r =cos ((pi)/(2^r))+isin((pi)/(2^r)) then Z_(1).Z_(2).Z_(3)"…….." upto oo equals

If z= cos((8pi)/11)+isin((8pi)/11),i=sqrt(-1) then the value of Re(z+z^2+z^3+z^4+z^5) is lambda then 20lambda^2 =