NO.PZ2020021205000058
问题如下：
A stock price is currently 50. Its volatility is 20% per annum. The risk-free rate is 4% per annum with continuous compounding. value an option that pays off max( - 2,400, 0) in six months where S is the stock price. (This is known as a power option.)
解释：
For the power option, the tree becomes as follows, and the value of the option is 408.363.
解析：
power option是一种奇异期权叫做幂期权，他与一般的期权的区别在于，在T时刻，看涨幂期权的价值=max{0，Sn -X}，而不是max{0，S-X}。该期权简单了解即可。
对于本题的这个幂期权，其价值=max{S2 -X，0}。具体的二叉树如下：
1、老师好，这道题的u（p）和d（1-p）分别是多少啊？
2、红色方框是前往前折现再乘以对应的概率吗？
3、折现的利率，折现到0.25段儿是4%乘以0.25，去年化？
我计算两个红色方框折现再乘以概率是744，不是738耶
4、标准差20%也要去年化吗？还是20%*0.25^0.5就行？
