imation.

<P>
It frequently happens,  however, that a function does  not have useful
internal variables.
For instance, another element function
might have structural form
<BR>
<DIV ALIGN="RIGHT">

<!-- MATH
 \begin{equation}
f_2 (v_1, v_2) = v_1 \sin v_2,
\end{equation}
 -->
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f_2 (v_1, v_2) = v_1 \sin v_2,
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