You must first specify some structural equation for the relationship between TC and LC, (and other relevant variables).  Estimate this relationship using gretl.  (How you do this depends on your model and the possible presence of other endogenous models.)   You can then easily estimate the required marginal effect.<div>
<br></div><div>Best regards</div><div><br></div><div>John   <br><br><div class="gmail_quote">On 25 July 2011 21:28, Anutechia Asongu <span dir="ltr">&lt;<a href="mailto:simplice_peace@yahoo.com">simplice_peace@yahoo.com</a>&gt;</span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"><table cellspacing="0" cellpadding="0" border="0"><tbody><tr><td valign="top" style="font:inherit">Hi all,<br>       Say I have a two series: Total Cost(TC) and Labour Cost(LC). I wish to obtain another series for the partial derivative of TC with respect to LC (dTC/dLC). Any hint on how this could be done via Grelt. <br>
      Thanks<br></td></tr></tbody></table><br>_______________________________________________<br>
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