dynamic construction of path based on param

I want to dynamically construct a path based on a
param called $course. Here is my current code:

<xsl:if test='contains($course, "510")'>
	<xsl:variable name="path" select="x510" />
</xsl:if>

<xsl:if test='contains($course, "340")'>
	<xsl:variable name="path" select="x340" />
</xsl:if>


<xsl:apply-templates select='syllabus/$path'/>

When I run the transformation the transformer responds
with "pattern empty," which tells me that it is not
changing the $path variable properly or that I have
not encoded it correctly. It is, however, receiving
the parameter correctly as I tested for that. How do I
construct this correctly? Also, ideally I'd just like
to use $course in the path. Thank you.

ra5en@xxxxxxxxx



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