'EOMONTH' is not a recognized built-in function name- SQL Server 2012

'EOMONTH' is not a recognized built-in function name- SQL Server 2012

I installed the SQL Server 2012- Developer edition. When I apply SELECT
@@version, I get: Microsoft SQL Server 2005 - 9.00.5000.00 (Intel X86) Dec
10 2010 10:56:29 Copyright (c) 1988-2005 Microsoft Corporation Express
Edition on Windows NT 6.1 (Build 7601: Service Pack 1)
But when I go to help, then about, It shows that it's SQL Server 2012. I'm
trying to use the EOMONTH function and I'm getting an error that the
EOMONTH is unrecognizable built in function. Can anybody please help me
understand what's going on? Thanks!I'm fairly new to T-SQL.