来自《耶鲁大学开放课程：金融理论 第7集 第7集》

• 
  
  the stuff after 30 years isn't very important.
  所以三十年后的事情也不重要了
• 
  
  You have to be given an extra tenth.
  你会得到额外的十分之一
• 
  
  So it's 10 ninths times 8,000
  九分之十乘以八千
• 
  
  so it's 8,888 is what your annuity's going to be every year.
  结果是8888 这个数就是你的年费
• 
  
  So just to summarize it, to say it all again,
  我做个总结 重复一遍
• 
  
  we know how to compute perpetuities with ease,
  我们现在可以熟练的计算永续年金
• 
  
  and so if you want 100 dollars and a coupon forever,
  如果你想要一百美元的永续年金
• 
  
  and the interest rate's 8 percent
  利率是百分之八
• 
  
  this is 8,000 forever.
  你就一直付八千
• 
  
  If you only get it for a shorter amount of time,
  如果你只想要一段时间的
• 
  
  obviously you have to get more.
  很明显你要多付一些钱
• 
  
  How much more?
  多拿多少呢