--- loncom/homework/lonmaxima.pm	2017/03/07 16:04:35	1.36
+++ loncom/homework/lonmaxima.pm	2017/03/07 18:28:02	1.37
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # Interface routines to MAXIMA CAS
 #
-# $Id: lonmaxima.pm,v 1.36 2017/03/07 16:04:35 raeburn Exp $
+# $Id: lonmaxima.pm,v 1.37 2017/03/07 18:28:02 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -155,9 +155,6 @@ sub maxima_eval {
 
 sub compareterms {
     my ($socket,$terma,$termb)=@_;
-    if ($terma =~ m{\(\s*\([^)]*$}) {
-        return 'Error: blacklisted';
-    }
     my $difference='('.$terma.')-('.$termb.')';
     if (&blacklisted($difference)) { return 'Error: blacklisted'; }
     my $reply=&maximareply($socket,'trigsimp(trigreduce('.$difference.'));');
@@ -169,7 +166,10 @@ sub compareterms {
 sub maxima_check {
     my ($response,$answer,$reterror) = @_;
     my $socket=&connect();
-    my $reply=&compareterms($socket,$response,$answer);
+    my $reply=&maximareply($socket,$response.';');
+    unless ($reply=~/^Error\:/) {
+        $reply=&compareterms($socket,$response,$answer);
+    }
     &disconnect($socket);
     # integer to string mappings come from capaParser.h
     # 1 maps to 'EXACT_ANS'