cosh

# File lib/cmath.rb, line 232
  def cosh(z)
    begin
      if z.real?
        RealMath.cosh(z)
      else
        Complex(RealMath.cosh(z.real) * RealMath.cos(z.imag),
                RealMath.sinh(z.real) * RealMath.sin(z.imag))
      end
    rescue NoMethodError
      handle_no_method_error
    end
  end