If `2+z+z^4=0, where z` is a complex number then` (A) `1/2 lt|z|lt1` (B) `1/2lt|z|lt1/3` (C) `|z|ge1` (D) none of these

If f(z)=(7-z)/(1-z^2) , where z=1+2i , then |f(z)| is (a)(|z|)/2 (b) |z| (c) 2|z| (d) none of these

z is a complex number satisfying z^(4)+z^(3)+2z^(2)+z+1=0 , then |z| is equal to

If z^(2)+z+1=0 where z is a complex number, then the value of (z+(1)/(z))^(2)+(z^(2)+(1)/(z^(2)))^(2)+...+(z^(6)+(1)/(z^(6)))^(2) is

If z_1 and z_2 are two complex numbers for which |(z_1-z_2)(1-z_1z_2)|=1 and |z_2|!=1 then (A) |z_2|=2 (B) |z_1|=1 (C) z_1=e^(itheta) (D) z_2=e^(itheta)

If z is a complex number satisfying |z|^(2)-|z|-2 lt 0 , then the value of |z^(2)+zsintheta| , for all values of theta , is