MatchingDynamicGraphs
Matching Problems With Dynamic Graphic Images
This PG code shows how make a matching problem that uses dynamically generated images.
| PG problem file | Explanation |
|---|---|
DOCUMENT(); loadMacros( "PGstandard.pl", "PGgraphmacros.pl", "PGunion.pl", "imageChoice.pl", ); TEXT(beginproblem()); $refreshCachedImages = 1; |
Initialization:
We need to include the macros file |
$a = random(1,4,1);
$b = random(1,4,1);
# four sequences
@seq = ();
$seq[0] = "s_n = $a - $b/n";
$seq[1] = "s_n = $a + (-1)^n/n";
$seq[2] = "s_n = $a/n";
$seq[3] = "s_n = $a + $b/n";
# handy routine for generating sequence values
sub sn {
my ( $snum, $nval ) = @_;
if ( $snum == 0 ) { return( $a - $b/$nval ); }
elsif ( $snum == 1 ) { return( $a + ((-1)**$nval)/$nval ); }
elsif ( $snum == 2 ) { return( $a/$nval ); }
elsif ( $snum == 3 ) { return( $a + $b/$nval ); }
else { return(1); } # shouldn't ever happen; bail out
}
# make graphs for each
@gr = ();
foreach my $i (0..3) {
$gr[$i] = init_graph(-1,-1,10,($a+$b),'axes'=>[0,0],'grid'=>[1,1]);
foreach my $j (1..10) {
$gr[$i]->stamps(closed_circle($j, sn($i, $j), 'blue') );
}
}
@QA = ();
foreach my $i (0..3) { push( @QA, "\($seq[$i]\)", $gr[$i] ); }
$ml = new_image_match_list(
link => 1, # do not link to separate image
size => [200,200], # image size in pixels
tex_size => 450, # tex size in precent times 10
columns => 2, # number of columns
separation => 20, # separation between image columns
);
$ml->rf_print_q(~~&pop_up_list_print_q); # use pop-up-lists
$ml->ra_pop_up_list([ No_answer=>"?", A=>"A", B=>"B", C=>"C", D=>"D"] );
$ml->qa(@QA); # set the questions and answers
$ml->choose(4); # select 4 of them
#$ml->choose_extra(0); # and show the other 1
|
Setup:
We define a few sequences and a subroutine for calculating them. (We could have used MathObjects formulas to do this, but decided not to.)
Then, we define an array of graphs and add the plots of the sequences to them. We create an array
We create a |
BEGIN_TEXT
\{
ColumnTable(
"Match the graphs with the corresponding formulas.".
$ml->print_q() # no period!
, # comma!
$BCENTER.
$ml->print_a().
$BR.
"(Click on a graph to enlarge it)".
$ECENTER # no period!
, # comma!
indent => 0, separation => 30, valign => "TOP"
)
\}
END_TEXT
|
Main Text:
We use a |
install_problem_grader(~~&std_problem_grader);
$showPartialCorrectAnswers = 0;
ANS(str_cmp($ml->ra_correct_ans));
foreach my $i (0..3) {
$a[$i] = $ml->ra_correct_ans->[$i];
}
BEGIN_SOLUTION
$PAR SOLUTION $PAR
The formulas match as follows:
1 matches graph $a[0],
2 matches graph $a[1],
3 matches graph $a[2], and
4 matches graph $a[3].
END_SOLUTION
ENDDOCUMENT();
|
Answer Evaluation:
The answer evaluation is as expected. We can access the correct answers, store them in a variable, and use them in the solution via |
