ComplexExpand doc corrections/completions

mathics/builtin/numbers/hyperbolic.py

@@ -261,14 +261,17 @@ class ComplexExpand(SympyFunction):
         <dl>
           <dt>'ComplexExpand[$expr$]'
           <dd>expands $expr$ assuming that all variables are real.
+
+          <dt>'ComplexExpand[$expr$,{$x1$,$x2$, ...}]
+          <dd>expands $expr$ assuming that variables matching any of the $xi$ are complex.
         </dl>
 
         Note: we get equivalent, but different results from WMA:
 
         >> ComplexExpand[3^(I x)]
          = 3 ^ (-Im[x]) Re[3 ^ (I Re[x])] + I Im[3 ^ (I Re[x])] 3 ^ (-Im[x])
 
-        Assume that both and are real:
+        Assume that both $x$ and $y$ and are real:
         >> ComplexExpand[Sin[x + I y]]
          = Cosh[y] Sin[x] + I Cos[x] Sinh[y]
 
@@ -289,7 +292,7 @@ class ComplexExpand(SympyFunction):
         >> ComplexExpand[Abs[2^z Log[2 z]], z]
          = Abs[I Arg[Re[z] + I Im[z]] + Log[4 Im[z] ^ 2 + 4 Re[z] ^ 2] / 2] 2 ^ Re[z]
 
-        Specify that a variable is take to be complex:
+        Specify that variable $z$ is taken to be complex:
         >> ComplexExpand[Re[2 z^3 - z + 1], z]
          = 1 - Re[z] + 2 Re[z] ^ 3 - 6 Im[z] ^ 2 Re[z]
     """