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1)

Let   w=3+i2  and   P={Wn:n=1,2,3...}   Further

  H1={zϵC;Rez>12}     and

H2={zϵC;Rez<12}

where C is the set of all complex numbers, if   z1PH1,z2PH2    and O represents the origin, then   z1Oz2 is equal to 


A) π2

B) π6

C) 2π3

D) 5π6

Answer:

Option C,D

Explanation:

Concept involved

 It is simple representation of points on argand plane and to find the angle between the points

 here,  P=Wn=(cosπ6+isinπ6)n

  =cosnπ6+isinnπ6

 H1={ZC:Re(z)>12}

    PH1 represents those points for which cosnπ6 is +ve

it belongs to I to IV quadrant

    z1=PH1=cosπ6+isinπ6

 or    cos11π6+isin11π6

         z1=32+i2or32i2    .....(i)

 Similarly ,   z2=PH2 i,e.   those points for which 

 cosnπ6<0

1352021948_m5.JPG

      z2=cosπ+isinπ,cos5π6

                                     +isin5π6,cos7π6+isin7π6

 z2=1,32+i2,32i2

 Thus,  z1Oz2=2π3,5π6,π