## WeBWorK Problems

### ERROR: non-zero status 256: Bad file descriptor

by Ron Vaillancourt -
Number of replies: 0

This problem viewing the equation in images format produces the following display and errors. Any help is greatly appreciated !

## DESCRIPTION
##   Approximate an Integral Using Riemann Sums
## ENDDESCRIPTION

## KEYWORDS('Definite', 'Integral', 'Approximate', 'Riemann Sum')
## Tagged by nhamblet

## DBsubject('Calculus')
## DBchapter('Techniques of Integration')
## DBsection('Approximate Integration')
## Date('')
## Author('')
## Institution('ASU')
## TitleText1('')
## EditionText1('')
## AuthorText1('')
## Section1('')
## Problem1('')

DOCUMENT();        # This should be the first executable line in the problem.

"PG.pl",
"PGbasicmacros.pl",
"PGchoicemacros.pl",
"PGauxiliaryFunctions.pl"
);

TEXT(beginproblem());
$showPartialCorrectAnswers = 1;$a = random(1,5,1);      ## left endpoint
$dx = random(1,2,1); ## delta x$n = random(3,4,1);
$b =$a + $n*$dx;            ## right endpoint, n subdivisions

$c = random(2,4,1); sub myfunc {$x = shift @_;
return $x**2 +$c*$x; } BEGIN_TEXT Estimate the area under the graph of $$f(x)= x^2 + c x$$ on the interval $$[a, b]$$ using $$n$$ approximating rectangles and left endpoints.$BR \{ans_rule(30)\}

END_TEXT

if ($n == 3) {$ans = $dx* (myfunc($a)+myfunc($a+$dx)+myfunc($a+2*$dx));
}

if ($n == 4) {$ans = $dx* (myfunc($a)+myfunc($a+$dx)+myfunc($a+2*$dx)+myfunc($a+3*$dx));
}

ANS(num_cmp(\$ans));

ENDDOCUMENT();        # This should be the last executable line in the problem.

# testcourse-1: Problem 1

This set is visible to students.

(1 pt) settestcourse-1/leftsum_1.pg
Estimate the area under the graph of on the interval using approximating rectangles and left endpoints.

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View equations as:
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images
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• cd /opt/webwork/webwork2/tmp/ImageGenerator.cg5342XM && /bin/mv /opt/webwork/webwork2/tmp/ImageGenerator.cg5342XM/equation1.png /opt/webwork/webwork2/htdocs/tmp/equations/6f/5e1a181d257fd53e477b73198f27661.png returned non-zero status 256: Bad file descriptor at /opt/webwork/pg/lib/WeBWorK/PG/ImageGenerator.pm line 401.
• cd /opt/webwork/webwork2/tmp/ImageGenerator.cg5342XM && /bin/mv /opt/webwork/webwork2/tmp/ImageGenerator.cg5342XM/equation3.png /opt/webwork/webwork2/htdocs/tmp/equations/70/1184bb64ba9bb2d7bb89f6d7c90b481.png returned non-zero status 256: Bad file descriptor at /opt/webwork/pg/lib/WeBWorK/PG/ImageGenerator.pm line 401.
• cd /opt/webwork/webwork2/tmp/ImageGenerator.cg5342XM && /bin/mv /opt/webwork/webwork2/tmp/ImageGenerator.cg5342XM/equation2.png /opt/webwork/webwork2/htdocs/tmp/equations/7f/731359622cd87aa269961264232bfe1.png returned non-zero status 256: Bad file descriptor at /opt/webwork/pg/lib/WeBWorK/PG/ImageGenerator.pm line 401.