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Number of complex number satisfying |z|=1 and |z/z(bar) +zbar/z|=1, is

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Solution: left | z 
ight |=1Rightarrow z=(cos	heta +isin	heta ) for some 	heta in (0,2pi )

             Now,           left | z 
ight |=1Rightarrow left | z 
ight |^2=1Rightarrow zarz=1

            Thus,      z/arz+arz/z=z^2+1/z^2

               Rightarrow      (cos	heta +isin	heta )^2+(cos	heta -isin	heta )^2=2(cos2	heta )

              	herefore      left | z/arz+arz+z 
ight |=1Rightarrow left | cos2	heta 
ight |=1/2

             Rightarrow     cos2	heta =pm 1/2

          2	heta =pi /3,2pi /3,4pi /3,5pi /3,7pi /3,8pi /3,10pi /3,11pi /3

         Hence , there are 8 value of z.  

Posted by

Deependra Verma

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