Yearly Discount Price By 20%

[vdanelia]

Hello Friends.


At first look i thought that it was very easy to implement, but when i realize everything that i want.. It's so hard to implement.

I'll Try To explain step by step what must be done...

I have 3 Text boxes:
1. DateofPurchase -Date/Time (I will enter the product date of purchase), let's say it is 2/4/2011

2. Price (I will enter the product price) Let's say it is 1000$
3. Discount (Here is the problem) this field must display (Calculate) 20% of discount of 1000% at 2/4/2012, the calculated price will be 800$ ("1000$ - 20% = 800$), after one year in 2/4/2013 the discount must be ("800$ - 20%), and this must go while the price will become "0"

How to fulfill this ?

[weekend00]

Discount: =0.8^(year(date())-year(DateofPurchase)-1-(format(date(),"mmdd")>=format(DateofPurchase,"mmd d"))) * price