问题如下：
A stock index is 3,000, the risk-free rate is 8% per year, and the dividend yield on the index is 3% per year (both expressed with annual compounding). What should the one-year futures price of the index be?
解释：
The one-year futures price is
3,000 *1.08/ 1.03= 3145.63
请问为什么dividend 是%形式，t=0时刻，so/(1+%)^t而不是so-so*%/(1+rf)^t呢