If the parameters are integers
DECLARE @Month int = 2
DECLARE @Year int = 2014
SELECT
DATEADD(month,(@Year*12-22800)+(@Month-1),0) AS [SatrtDate],
DATEADD(daY,-1,DATEADD(month,(@Year*12-22800)+@Month,0)) AS [EndDate]
Far away is close at hand in the images of elsewhere.
Anon.