# LimitsOfIntegration

## Answer Blanks in the Limits of an Integral

This PG code shows how to put answer blanks into the limits of an integral.

PG problem file Explanation
DOCUMENT();
"PGstandard.pl",
"MathObjects.pl",
"PGunion.pl",
);
TEXT(beginproblem());


Initialization: We need to include the macros file PGunion.pl.

Context("Numeric");

#
# display the integral nicely
#
if ($displayMode eq 'TeX') {$integral =
'$\int_{'.ans_rule(4).'}^{'.ans_rule(4).'}'. ans_rule(10).'\,dx$';
} else {
$integral = BeginTable(). Row(['$$\displaystyle \int$$', ans_rule(4).$BR.$BR.ans_rule(4), ans_rule(10), '$$dx$$.'],separation=>2). EndTable(); }  Setup: We define a mode dependent integral with three answer blanks. Context()->texStrings; BEGIN_TEXT Set up the integral of $$x^2$$ from 1 to 3.$PAR
$BCENTER$integral
$ECENTER END_TEXT Context()->normalStrings;  Main Text: The problem text section of the file is as we'd expect. We insert the integral with answer blanks using $integral.

\$showPartialCorrectAnswers = 1;

ANS( Real(3)->cmp() );
ANS( Real(1)->cmp() );
ANS( Formula("x^2")->cmp() );

ENDDOCUMENT();