SharePoint 2010: Show QuickLaunch in web part page.

1.   Remove this place holder from webpart page

< asp:Content ContentPlaceHolderId="PlaceHolderNavSpacer" runat="server"></asp:Content>

< asp:Content ContentPlaceHolderId="PlaceHolderLeftNavBar" runat="server"></asp:Content>

2 Remove below code from web part page


<SharePoint:UIVersionedContent ID="WebPartPageHideQLStyles" UIVersion="4" runat="server">
<ContentTemplate>
<style type="text/css">
body #s4-leftpanel {
display:none;
}
.s4-ca {
margin-left:0px;
}
</style>
</ContentTemplate>
</SharePoint:UIVersionedContent>