# [LON-CAPA-users] Sketching Graphs

Gerd Kortemeyer korte at lite.msu.edu
Fri Feb 3 16:53:17 EST 2012

```Hi,

On Feb 3, 2012, at 4:20 PM, Seema Ali wrote:

> How do you create a problem (through Geogebra) to get students to sketch a graph and mark it?

We don't advertise this yet, since we still test it. But I think it's good by now. Here's an example.

- Gerd.

<problem>
<script type="loncapa/perl">\$x=&random(5,10,1);</script>
<startouttext />
Make a sketch of the electrostatic potential (zero at infinity) of a negative point charge located at x=\$x m.
<endouttext />
<functionplotresponse xaxisvisible="yes" xlabel="x [m]" gridvisible="yes" ylabel="V(x) [V]" id="11" xmax="30" yaxisvisible="yes" xmin="-4" ymin="-10" ymax="10" answerdisplay="-4/abs(x-\$x)">
<functionplotelements>
<spline initx="-2" inity="0" index="A" order="2" scalex="4" />
<spline index="B" order="2" initx="12" inity="0" scalex="4" />
</functionplotelements>
<functionplotruleset>
<functionplotrule relationship="eq" value="undef" derivative="0" xinitial="\$x" index="chargeposition" derivativeorder="0" />
<functionplotrule relationship="lt" value="0" derivativeorder="0" xinitiallabel="start" xfinallabel="chargeleft" index="negleft" />
<functionplotrule relationship="lt" value="0" derivativeorder="1" xinitiallabel="start" xfinallabel="chargeleft" />
<functionplotrule relationship="le" value="0" derivativeorder="2" xinitiallabel="start" xfinallabel="chargeleft" percentageerror="20" />
<functionplotrule relationship="eq" xinitiallabel="chargeleft" xfinallabel="chargeright" value="undef" derivativeorder="0" />
<functionplotrule relationship="lt" value="0" derivativeorder="0" xinitiallabel="chargeright" xfinallabel="end" index="negright" />
<functionplotrule relationship="gt" value="0" derivativeorder="1" xinitiallabel="chargeright" xfinallabel="end" />
<functionplotrule relationship="le" value="0" derivativeorder="2" xinitiallabel="chargeright" xfinallabel="end" percentageerror="20" />
</functionplotruleset>

<hintgroup showoncorrect="no">
<hintpart on="chargeposition">
<startouttext />The charge is not in the correct position.<endouttext />
</hintpart>
<hintpart on="negleft">
<startouttext />The potential is zero at negative infinity, and the charge is negative.<endouttext />
</hintpart>
<hintpart on="negright">
<startouttext />The potential is zero at positive infinity, and the charge is negative.<endouttext />
</hintpart>
</hintgroup>
</functionplotresponse>
</problem>
```