Oracle Finding Last_Day of Previous months

Hi

Following sql helps you to get previous months  last_day values:

Current Date:
select  trunc(sysdate) from dual

22.01.2016

Results:
-- One month before
select   ADD_MONTHS (LAST_DAY (TRUNC (SYSDATE)),-1)   from dual
31.12.2015

-- Eleven months before
select   ADD_MONTHS (LAST_DAY (TRUNC (SYSDATE)),-11)   from dual
28.02.2015