I have a date let 28-02-2012(dd-mm-yyyy)

if i want to add number of months depending on picklist value say

"monthly"

date become 28-03-2012 or 30-03-2012

"Quarterly"--> 28-05-2012

"halfyearly"--> 28-08-2012

yearly-> 28-02-2013

if date is 15-12-2012

monthly->15-01-2013

quarterly->15-03-2013

halfyearly->15-06-2013

yearly->15-12-2014

how its formula is to be written

I have a date let 28-02-2012(dd-mm-yyyy)

if i want to add number of months depending on picklist value say

"monthly"

date become 28-03-2012 or 30-03-2012

"Quarterly"--> 28-05-2012

"halfyearly"--> 28-08-2012

yearly-> 28-02-2013

if date is 15-12-2012

monthly->15-01-2013

quarterly->15-03-2013

halfyearly->15-06-2013

yearly->15-12-2014

how its formula is to be written