How do you find z, z^2, z^3, z^4z,z2,z3,z4 given z=sqrt2/2(1+i)z=22(1+i)?

1 Answer
Dec 17, 2016

z=sqrt2/2(1+i)z=22(1+i), z^2=iz2=i, z^3=sqrt2/2(-1+i)z3=22(1+i) and z^4=-1z4=1

Explanation:

z=sqrt2/2(1+i)z=22(1+i)

= (sqrt2/2+isqrt2/2)(22+i22) and in trigonometric form

= (cos(pi/4)+isin(pi/4))(cos(π4)+isin(π4)) or in exponential

= e^(ipi/4)eiπ4

Hence z^2=e^(i(2pi)/4)=e^(ipi/2)=(cos(pi/2)+isin(pi/2))=iz2=ei2π4=eiπ2=(cos(π2)+isin(π2))=i

and z^3=e^(i(3pi)/4)=(cos((3pi)/4)+isin((3pi)/4))=-sqrt2/2+isqrt2/2z3=ei3π4=(cos(3π4)+isin(3π4))=22+i22

= sqrt2/2(-1+i)22(1+i)

and

z^4=e^(i(4pi)/4)=e^(ipi)=(cospi+isinpi)=-1z4=ei4π4=eiπ=(cosπ+isinπ)=1