(* Created by Wolfram Mathematica 6.0 *)
5.5889900844579525*^-15*
 Sqrt[
  -(Im[f/(-1162.735375511243*f^2 + 
       ((45.4471855128244 + 4.544718551282395*^-6*I)*f^3*
         Sqrt[5206.842810135252 + (0.3313099823884882 + 6.626199647769764*^-8*
              I)*f^2]*(Sqrt[(2.4257726427661788 - 4.851545285532358*^-7*I)*
             (-72.15845626214056 + Sqrt[5206.842810135252 + 
                (0.3313099823884882 + 6.626199647769764*^-8*I)*f^2])]*
           Sin[0.4*Sqrt[(2.4257726427661788 - 4.851545285532358*^-7*I)*(
                -72.15845626214056 + Sqrt[5206.842810135252 + 
                  (0.3313099823884882 + 6.626199647769764*^-8*I)*f^2])]] + 
          Sqrt[(2.4257726427661788 - 4.851545285532358*^-7*I)*
             (72.15845626214056 + Sqrt[5206.842810135252 + 
                (0.3313099823884882 + 6.626199647769764*^-8*I)*f^2])]*
           Cos[0.4*Sqrt[(2.4257726427661788 - 4.851545285532358*^-7*I)*(
                -72.15845626214056 + Sqrt[5206.842810135252 + 
                  (0.3313099823884882 + 6.626199647769764*^-8*I)*f^2])]]*
           Tanh[0.4*Sqrt[(2.4257726427661788 - 4.851545285532358*^-7*I)*(
                72.15845626214056 + Sqrt[5206.842810135252 + 
                  (0.3313099823884882 + 6.626199647769764*^-8*I)*f^2])]]))/
        ((-22.7235927564122 - 2.2723592756411974*^-6*I)*f^3*
          (Cos[0.4*Sqrt[(2.4257726427661788 - 4.851545285532358*^-7*I)*(
                -72.15845626214056 + Sqrt[5206.842810135252 + 
                  (0.3313099823884882 + 6.626199647769764*^-8*I)*f^2])]] - 
           Sech[0.4*Sqrt[(2.4257726427661788 - 4.851545285532358*^-7*I)*(
                72.15845626214056 + Sqrt[5206.842810135252 + 
                  (0.3313099823884882 + 6.626199647769764*^-8*I)*f^2])]]) + 
         2848.7016700025456*f^2*Sin[0.4*Sqrt[(2.4257726427661788 - 
               4.851545285532358*^-7*I)*(-72.15845626214056 + Sqrt[
                5206.842810135252 + (0.3313099823884882 + 
                   6.626199647769764*^-8*I)*f^2])]]*
          Tanh[0.4*Sqrt[(2.4257726427661788 - 4.851545285532358*^-7*I)*
              (72.15845626214056 + Sqrt[5206.842810135252 + 
                 (0.3313099823884882 + 6.626199647769764*^-8*I)*f^2])]]))]/
    f^2)]