## WeBWorK Main Forum

### Turning off 'Messages' in Answer Checker

by Spyro Roubos -
Number of replies: 1
I am having difficulties with a Calculus I question:

Given a function, I ask the student:

On what interval(s) is the function increasing: ____?

On what interval(s) is the function decreasing: ____?

-where "NA" can be entered if there is no such interval of one type.

The issue is as follows:
(say the correct answer to the first blank is "(-inf,inf)" and the second is "NA"). If the student enters: "(1,2)" for the first blank, s/he receives the message "Your left endpoint is incorrect, Your right endpoint is incorrect". However, if the student enters "(1,2)" for the second blank, the answer checker is expecting to compare a string and will gives no message.

There is an added ambiguity in the situation of a student entering "(1,2) U (4,5)" in either blank, which also results in no message.

Is there a way of turning off messages? -or an easy way of editing the messages?

Here is the code:
---------------------------------------------------------
DOCUMENT();

loadMacros(
"PGstandard.pl",
"MathObjects.pl",
# "PGcourse.pl",
"source.pl",
);

$showPartialCorrectAnswers = 1; Context("Interval"); Context()->strings->add(NA=>{}, "Not Applicable"=>{alias=>'NA'});$aa = non_zero_random(-10,10,1);

$Funct = Formula("e^x/($aa + e^x)");
$Deriv =$Funct->D;

if($aa > 0) {$Interv1 = Interval("(-INF,INF)");
$Interv2 = String("NA"); } else {$Interv1 = String("NA");
$Interv2 = Interval("(-INF,log(-$aa))U(log(-$aa),INF)"); } TEXT(beginproblem()); Context()->texStrings; BEGIN_TEXT Consider the function $f(x)=\frac{e^x}{aa + e^x}$$BR

Then $$f'(x)$$ = \{ ans_rule()\}
$PAR The interval of increase for $$f(x)$$ is: \{ ans_rule()\}$PAR
The interval of decrease for $$f(x)$$ is: \{ ans_rule()\}
$PAR END_TEXT ANS($Deriv->cmp);
ANS($Interv1->cmp(typeMatch=>Value::Interval)); ANS($Interv2->cmp(typeMatch=>Value::Interval));

ENDDOCUMENT();
-----------------------------------------------
Thanks,
Spyro Roubos
In reply to Spyro Roubos

### Re: Turning off 'Messages' in Answer Checker

by Davide Cervone -
You can prevent the Interval checker from issuing its message by adding
      showEndpointHints => 0, showEndTypeHints => 0

to your cmp() calls.

In order to edit the messages you would need to install a post filter to the answer checker. (There is also another way to do it that uses a mechanism intended for allowing the error messages to be translated into another language. That could be used to convert the message to another form or to a blank message, but the *Hints flags above are probably your best choice.)

Davide