** Using WeBWorK **

- My output:

If sin A = 4/9 and

pi/2 < A < pi

, then cos A =

should be

If sin A = 4/9 and pi/2 < A < pi, then cos A =

I am getting "\pi/2 < A < \pi" as an image , and it's OK.

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I have not seen this problem before. Could you post the pg code for the problem?

John

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##DESCRIPTION ##KEYWORDS('linear albebra', 'vector space', 'linear transformation') ## ##ENDDESCRIPTION

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

loadMacros( PG.pl, PGbasicmacros.pl, PGchoicemacros.pl, PGanswermacros.pl, PGgraphmacros.pl, PGnumericalmacros.pl, PGstatisticsmacros.pl );

TEXT(beginproblem()); $showPartialCorrectAnswers = 1;

$d = non_zero_random(2,5,1); $a = non_zero_random(2,5,1); $e = $d*$a -1;

$b = non_zero_random(-4,4,1); $c = non_zero_random(-4,4,1); $f = non_zero_random(-4,4,1); $g = non_zero_random(-4,4,1);

$i = non_zero_random(-4,4,1); $j = random(2,5,1);

$ans1 = ...; $ans2 = ...;

BEGIN_TEXT

$BR If ( T: P_1 rightarrow P_1 ) is a linear transformation such that

( T(1+$a x) = $b + $c x) and ( T($d + $e x) = $f + $g x, ) then

( T($i - $j x) = )\{ans_rule(5)}(+)\{ans_rule(5)}(x).

END_TEXT

ANS(num_cmp($ans1)); ANS(num_cmp($ans2));

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

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Unfortunately, lots of backslashes get filtered by the discussion board (also double quote marks). So, there is an outside chance that backslashes are somehow involved in the problem. But, this problem worked fine for me.

The next few things I would try are:

• see if your browser will let you look at the source for the page which has the problem displayed. Some won't because the pages are supposed to expire instantly, but others will. You can see if the page has html forcing the line breaks.
• look at the images (under html/tmp/png) with xv to make sure they look ok. They may look funny because of the transparent background, but they should look ok aside from that, with the whole image tightly cropped around the math. One guess is that the images are picking up lots of white space, making them extra wide so the browser thinks it needs to wrap the line.
• test preview/dvipng outside of webwork. One way would be to comment out the line in system/lib/Imagegenerator which cleans up tex files, load a page which needs new images, and then take the latex file. Run latex on it, then dvipng on the result. You should get png files which look nice (no transparent background by default) and they should be small - tightly cropped around the math.

John

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I found the problem thanx to your suggestion #2, but I don't know how to solve it. Problem is that images are picking up lots of white spaces, for example dimension for an image is 3485x20 pixels. Any suggestion how to correct this?

Regards Zoran.

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My guess is a problem with the setup for preview/dvipng. Part of what preview does is to set up the tightly cropped images. I will try to input a test file here, but beware of lost backslashes:

\documentclass[10pt]{report}

\usepackage[active,textmath,displaymath]{preview}
\begin{document}
Here is \(y=x^2\), and a displayed equation like
\(\displaystyle{ f(z) = \frac{3z+1}{2z-1} .} \)

Finally another inline image \( \Gamma(z) = \int_0^{\infty} t^{z-1} e^{-t}
\, dt\).

\end{document}

John

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You got the point. I generated all three images and they are not looking good from the point of width. Do you know how to change the setup?

Regards Zoran

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In testing WeBWorK 1.9, I downloaded and installed dvipng-0.4 on a Red Hat 9.0 system and had maybe related problems (the images came out as very long white bars). Backing off to version 0.3 solved the problem.

Arnie

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Sorry for late response. I also lowered my version on dvipng from 0.4 to 0.3 and it's working fine. I am using WebWork 1.8 on RedHat 9.0.

Thanx to John and Arnie for all insight.

Regards Zoran.

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Sorry for all the commotion around dvipng 0.4.

Dvipng 0.5 solves this issue (but has a bug in the installation of the docs---which will be fixed in 0.6).

/Jan-Åke

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* /usr/local/bin/dvipng -x4000 -bgTransparent -Q6 -mode toshiba -D180 a-prob5image.dvi >>/dev/null 2>>/dev/null -- FAILED in ImageGenerator.pm returned 32512 at /opt/webwork/system/lib//ImageGenerator.pm line 192. ##More details: -------- ImageGenerator::render called at /opt/webwork/system/cgi/cgi-scripts/processProblem8.pl line 470

Help -- rac

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dvipng

(or possibly /usr/local/bin/dvipng) will give you a help text where the version info is included.

/JÅ

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It is using version 0.4 .

-- rac

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