For a non-zero complex number 𝑧, let arg (𝑧) denote the principal argument with .−π

a) arg(-1-i)=-3π4 b) f(t)=arg(-1+it)=π-tan-1(t),t≥0-π+tan-1(t)t<0 Discontinuous at t=0 c) argz1z2-argz1+argz2=argz1-argz2+2nπ-argz1+argz2=2nπ d) argz-z1z2-z3z-z3z2-z1=π⇒z-z1z2-z3z-z3z2-z1 is real. ⇒z,z1,z2,z3 are concyclic