code: def cos_1(a=1):
      r
  
      def lhs(x):
          return np.exp(-a**2*x**2)
  
      def rhs(b):
          return np.sqrt(np.pi)*np.exp(-b**2/(4*a**2))/(2*a)
  
      return Ghosh('cos', lhs, rhs)
docs: r"""Fourier cosine transform pair cos_1 ([Ande75]_).