# [LON-CAPA-users] Having an equation or a range as a response

Gerd Kortemeyer korte at lite.msu.edu
Thu Jan 19 21:51:53 EST 2012

```Hi,

On Jan 19, 2012, at 8:39 PM, Seema Ali wrote:

> An example would be:
>
> State the equation for the asymptote for the graph y=10^(x+7)+8.
>
> I would like the student to enter the entire equation into the answer box.

So that would be x=7 or y=8, correct?

<problem>
<script type="loncapa/perl">\$a=&random(3,8,1);
\$b=\$a+&random(2,5,1);
\$sample="x=\$a or y=\$b would be correct";
</script>

<startouttext />
Given an equation for an asymptote of <m eval="on">\$y=10^{x+\$a}+\$b\$</m>.
<endouttext />

# Get left and right side of equation
(\$left,\$right)=split(/\s*\=\s*/,\$submission);

# We want something on both sides of the equation
unless ((\$left=~/\w/) && (\$right=~/\w/)) { return 'BAD_FORMULA'; }

# Use computer algebra system to see if it agrees to one of our desired equations
if (&cas('maxima',"(\$left)-(\$right)-(x-\$a)") eq '0') { return 'EXACT_ANS'; }
if (&cas('maxima',"(\$left)-(\$right)-(y-\$b)") eq '0') { return 'EXACT_ANS'; }

return 'INCORRECT';