   #
   # ¯12○2          <=> ¯0.4161468365471J0.9092974268257
   # ¯12○2j3        <=> ¯0.02071873100224J0.04527125315609
+  # ¯11○2          <=> 0j2
+  # ¯11○2j3        <=> ¯3j2
   # 1e¯10>∣.5-1○○÷6 <=> 1 # sin(pi/6) = .5
   #  9○3j4         <=> 3
   # 11○3j4         <=> 4

    else if x instanceof Complex
      switch i
        when -12 then Complex.exp simplify -x.im, x.re
        when  9 then x.re
        when 11 then x.im
        else throw DomainError 'Unknown circular or hyperbolic function ' + i

    if typeof x is 'number'
      switch i
        when -12 then Complex.exp simplify 0, x
        when -11 then simplify 0, x
        when -7 then Math.log((1 + x) / (1 - x)) / 2 # arctanh
        when -6 then Math.log(x + Math.sqrt(x * x - 1)) # arccosh
        when -5 then Math.log(x + Math.sqrt(x * x + 1)) # arcsinh
