i) If z is a complex number such that z=k(cos@+isin@), where k is real, show that arg(z+k)=@/2
ii) Deduce that if z1, z2 and z3 are ANY three complex numbers at the vertices of an equilateral triangle then
(z1)^2+(z2)^2+(z3)^2=z1z2+z2z3+z1z3
iii) Given that 1+z+z^2+z^3=(1-z^4)/(1-z) and that...