Question #401a2

1 Answer
sjc
Nov 4, 2017

#0#

Explanation:

we will use De'Moivre's theorem

#(costheta+isintheta)^n=cosntheta+isinntheta#

#z=cos(pi/4)+isin(pi/4)#

#z^2=(cos(pi/4)+isin(pi/4))^2#

#:.z^2=cos((2pi)/4)+isin((2pi)/4)#

#z^2=cos(pi/2)+isin(pi/2)#

#Re(z^2)=cos(pi/2)=0#

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