25.
Write the following complex numbers in polar form and hence, find their modulus and argument.
Here, Let  Â
                            ...(i)
Equating real and imaginary parts, we get
      Â
                                         ...(ii)
                   Â
                                 ...(iii)
Squaring and adding (ii) and (iii), we get
   Â
                     r
2 =1Â Â Â Â Â Â Â Â Â Â Â Â
    r = 1
From (ii)Â Â Â Â Â Â Â Â Â Â Â
             Â
   Â
From (iii)Â Â Â Â Â Â Â Â Â (I)
          Â
     Â
Since,
Â
∴    lies in IVth quadrant
∴     Â
                Â
Putting in (i), we get
                 Â
Which is required polar form of z.
Hence,     Â
                      Â
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