Jun 26 2014 10:27 AM
the reason for this is because 10,000 is initial investment in the beginning of year. You need to understand the working of excel formula for this.
Desired result can be obtained by putting "=NPV(0.1,4000,4000,5000) -10000" in excel.
to understand the working of NPV excel formula goto to below mentioned link and see example 2 there.