问题如下图：
选项：
A. 
B. 
C. 
解释：
为什么FV=0，而不是PV=0? 还有就是 哪里看出先付年金？本题是之前付了几年的年金，现在开始收年金？
菲菲_品职助教 · 2018年08月26日
同学你好，本题的意思是，在很多年前这个投资者买了一个年金，第一笔payment的收入发生在今天，而且是求今天的年金现值，所以是先付年金，其实这个画个图就非常明了了。本题不是说之前付了几年的年金，现在开始收年金。对于本题，相当于投资者在多年前买了一笔年金，是一次性付款的，只是从今天开始才得到了第一笔收入，持续20年。等到20年之后，相当于你已经得到了最后一笔收入5000，除了这5000没有别的收入或者支出了。所以FV等于0。因为我们是要计算PV，相当于这20笔payment折现到今天，所以PV不会等于0。本题的图解如下：
由图可以很轻易的判断这是先付年金，如果是后付年金的话，第一笔payment应该发生在T=N+1才对。
lucky · 2018年08月27日
茅塞顿开，多谢菲菲！👍👍
菲菲_品职助教 · 2018年08月27日
加油哦💪🏻
lucky · 2018年08月27日
嗯嗯！😀😀
菲菲_品职助教 · 2018年08月27日
*纠个小错：我画的图中“N+20”应该改为“N+19”才对哦~不然就是21笔payment了。
lucky · 2018年08月27日
谢谢您细致的解答！多谢！
NO.PZ2015120604000011 问题如下 investor purchaseannuity many years ago. The first payment of the annuity is to receivetoy. Assume the payment of the annuity is $5,000 constanly , the periothe payment is 20 years. anthe scount rate is 12%, calculate the toy' value of the annuity: A.$37,347. B.$403,493. C.$41,829. C is correct.Unr the BGN mo.N = 20; PMT = -5,000; I/Y =12; FV = 0; CPT PV = 41,828.89. 这道题从哪里判断的是先付年金呀
NO.PZ2015120604000011 问题如下 investor purchaseannuity many years ago. The first payment of the annuity is to receivetoy. Assume the payment of the annuity is $5,000 constanly , the periothe payment is 20 years. anthe scount rate is 12%, calculate the toy' value of the annuity: A.$37,347. B.$403,493. C.$41,829. C is correct.Unr the BGN mo.N = 20; PMT = -5,000; I/Y =12; FV = 0; CPT PV = 41,828.89. 可以用后付年金的计算方式，用n=19来算么
NO.PZ2015120604000011问题如下 investor purchaseannuity many years ago. The first payment of the annuity is to receivetoy. Assume the payment of the annuity is $5,000 constanly , the periothe payment is 20 years. anthe scount rate is 12%, calculate the toy' value of the annuity: A.$37,347.B.$403,493.C.$41,829.C is correct.Unr the BGN mo.N = 20; PMT = -5,000; I/Y =12; FV = 0; CPT PV = 41,828.89.我最近错的题目全部都是先付后付判断不对导致的 要不就是时间折现点的N算的不对，有容易理解的方法吗
NO.PZ2015120604000011 问题如下 investor purchaseannuity many years ago. The first payment of the annuity is to receivetoy. Assume the payment of the annuity is $5,000 constanly , the periothe payment is 20 years. anthe scount rate is 12%, calculate the toy' value of the annuity: A.$37,347. B.$403,493. C.$41,829. C is correct.Unr the BGN mo.N = 20; PMT = -5,000; I/Y =12; FV = 0; CPT PV = 41,828.89. crecivetoy 意思不是于今天收到吗，不是今天存入呀，意思是多年前买的年金今天可以提取了，不应该是求fv嘛
NO.PZ2015120604000011 问题如下 investor purchaseannuity many years ago. The first payment of the annuity is to receivetoy. Assume the payment of the annuity is $5,000 constanly , the periothe payment is 20 years. anthe scount rate is 12%, calculate the toy' value of the annuity: A.$37,347. B.$403,493. C.$41,829. C is correct.Unr the BGN mo.N = 20; PMT = -5,000; I/Y =12; FV = 0; CPT PV = 41,828.89. 这道题pmt是-5000，我一直搞不清楚什么时候是用+什么时候-