The code

$graph_object->lb( new Label($xmin+0.1,0.05,'x','black','left','center'));

inserts the label x at the indicated point on the graph.

Can I insert a TeX label (like \(\frac{\pi}{2}\) in place of 'x'?

$pi_label = EV3("\(\frac{\pi}{2}\)");

$graph_object->lb( new Label($xmin+0.1,0.05,$pi_label,'black','left','center'));

might work (I haven't had a chance to test it.)

The EV3() subroutine is the one that translates Tex and other things in

the BEGIN_TEXT/END_TEXT blocks.

(see the problem text for details)

The graph image isn't changing. Even when I remove

the label command or change the label to something like

'*', the old label is drawn. It is as if the image is stored

permanantly somewhere on the disk and is oblivious to

changes in my code.

Here is my code:

$graph_object = init_graph(-2, -6, 2, 6,

'axes' => [0,0],

'grid' => [4,12],

'pixels' => [400,600]);

$g= sub{my $x=shift(); return $x**3;};

$fn=new Fun($g,$graph_object);

$p=1.570795;

$graph_object->moveTo(-$p,0);

$graph_object->lineTo(-$p,-$p**3);

$graph_object->stamps( closed_circle(-$p,-$p**3,'blue') );

$graph_object->lb( new Label(-$p+0.15,-$p**3,'P', 'black','left','center'));

$pi_label = EV3("\(-\pi/2\)");

$graph_object->lb( new Label($p,0.05,$pi_label,'black','left','center'));

############################

TEXT(beginproblem());

BEGIN_TEXT

Here is the graph of the function \(g(x)=x^3\)

problem 3.2.2 in your textbook (p180).

$BR

\{ image( insertGraph($graph_object) ) \} (Click on the image to enlarge

it.)

$BR

Specify

the \(y\)-coordinate of the point \( P \) on the given function. Give

an exact expression and also a calculator approximation rounded to three

decimal places. In the graph I put -pi/2 instead of \(-\frac{\pi}{2}\);

Remember that \(\pi=3.14159\ldots\).

$PAR

\( \hspace{.25in} \mbox{Exact value } = \) \{ ans_rule{20} \}

$PAR

\( \hspace{.25in} \mbox{Value to 3dp } = \) \{ ans_rule{20} \}

$BR

$BR

END_TEXT

############################

Context("LimitedNumeric");

loadMacros("fixedPrecision.pl"); # must come after Context is set.

$y = "-pi**3/8";

$n = FixedPrecision(3.876);

ANS(num_cmp($y));

ANS(num_cmp(-3.876));

############################

if ($showHints) {

}

if ($showSols) {

$twoinc = 2 * $inc;

$incsquared = $inc**2;

SOLUTION(EV3(<<'EOT'));

$BR <B>Solution</B>:

The \( x \) coordinate of \( P \) is \( -\pi/2 \) and \( P \) lies

on the graph of \( g(x) = x^3 \), so the \( y \) coordinate of

\( P \) must be \( y = (-\pi/2)^3 = -\pi^3/8 \simeq -3.876 \).

EOT

}

ENDDOCUMENT();

a bug in the browser. When I sign off and on, normal

behavior resumes. However, the code didn't work. y

Make sure that you use "shift reload" on your browser to make sure that the image is not being cached by

your browser. Having said that -- yes the image is also likely

cached on the machine as well. There is some effort made to insure that this image

is "current" but since you are doing something a bit outside the standard box

it's possible that in this case the refresh isn't behaving properly. It would take some experimenting

to figure out exactly what the problem is.

Take care,

Mike