How to Get Last Day of the week and Month

DECLARE @Date datetime
SET @Date = '2000/02/1'
SELECT DATEADD(dd,-(DATEPART(dw, @Date) - 1),@Date) AS 'First day of the week'
SELECT DATEADD(dd,-(DATEPART(dw, @Date) - 7),@Date) AS 'Last day of the week'
SELECT DAY(DATEADD(d, -DAY(DATEADD(m,1,@Date)),DATEADD(m,1,@Date))) AS 'Last day of the month'

SELECT convert(varchar, DATEADD(d, -DAY(DATEADD(m,1,@Date)),DATEADD(m,1,@Date)), 101) AS 'Last Date of the month'