Try this:
The Script code should be in RadCodeBlock tag outside the RadMultiPage, like this :
<telerik:RadCodeBlock ID="RadCodeBlock1" runat="server">
<script type="text/javascript">
$(document).ready(function (){
$("#<%=btn_jquerycall.Client%>").click(function () {
alert("Comming Soon!");
});
});
</script>
</telerik:RadCodeBlock>