如题,如果没有理解错的话.应该是累计密数正态分布吧..
但是没接触过.有人能给个网站或者文献什么的学习下吗?可以标价让我买(别太贵了).

Assume you have the opportunity to invest in a riskless project that will
generate $100 forever. It will cost you $750 today to make the investment.
Assume interest rates will either be 10% or 20% tomorrow and will stay that
way forever. Assume both states are equally likely under the risk neutral
measure.
Assume the current short rate (risk free rate) is 12%

PV in 1 year =1/2×(100/0.1)+1/2*(100/0.2)+100
= 850
NPV = (1/1.12) × 850 − 750
= 8.9

请问那个PV里面为什么要+100啊？