B为什么不对

NO.PZ2021061002000047 问题如下 A portfolio manager observes the prianTM of one-ye(r1) antwo-ye( r2) annucoupon government benchmark boncurrently available in the market. How the manager ctermine a breakevenreinvestment rate in one year’s time to help ci whether to invest now forone or two years? A.vi the square root of (1 + r2 ) (1 +r1 ) ansubtra1 to arrive a breakeven reinvestment rate for one yeinone year’s time. B.Set (1 +r1) multiplie1 plus thebreakeven reinvestment rate equto (1 + r2) 2 ansolve for the breakevenreinvestment rate. C.First substitute the one-yerate (r1)into the two-yebonpriequation to solve for the two-yespot or zerorate (z2 ), then set (1 + r1 ) × (1 + breakeven reinvestment rate) = (1 + z2 ) 2 ansolve for the breakeven reinvestment rate. 中文解析本题考察的是计算Implieforwarrates(IFR)。即题干说的观察到市场上现有的一年期(r1)和两年(r2)年期国债的收益率，想确定一年内的盈亏平衡再投资率。考察的公式为基于此公式，只有C描述正确。 如题，还有老师能不能讲一下我们是怎么用r1求z2的过程啊

NO.PZ2021061002000047问题如下 A portfolio manager observes the prianTM of one-ye(r1) antwo-ye( r2) annucoupon government benchmark boncurrently available in the market. How the manager ctermine a breakevenreinvestment rate in one year’s time to help ci whether to invest now forone or two years? A.vi the square root of (1 + r2 ) (1 +r1 ) ansubtra1 to arrive a breakeven reinvestment rate for one yeinone year’s time. B.Set (1 +r1) multiplie1 plus thebreakeven reinvestment rate equto (1 + r2) 2 ansolve for the breakevenreinvestment rate. C.First substitute the one-yerate (r1)into the two-yebonpriequation to solve for the two-yespot or zerorate (z2 ), then set (1 + r1 ) × (1 + breakeven reinvestment rate) = (1 + z2 ) 2 ansolve for the breakeven reinvestment rate. 中文解析本题考察的是计算Implieforwarrates(IFR)。即题干说的观察到市场上现有的一年期(r1)和两年(r2)年期国债的收益率，想确定一年内的盈亏平衡再投资率。考察的公式为基于此公式，只有C描述正确。 看了其他回答还是不太明白，请再详细一点，为什么要求z2以及怎么求的？还有零利率这个概念是什么意思

NO.PZ2021061002000047问题如下 A portfolio manager observes the prianTM of one-ye(r1) antwo-ye( r2) annucoupon government benchmark boncurrently available in the market. How the manager ctermine a breakevenreinvestment rate in one year’s time to help ci whether to invest now forone or two years? A.vi the square root of (1 + r2 ) (1 +r1 ) ansubtra1 to arrive a breakeven reinvestment rate for one yeinone year’s time. B.Set (1 +r1) multiplie1 plus thebreakeven reinvestment rate equto (1 + r2) 2 ansolve for the breakevenreinvestment rate. C.First substitute the one-yerate (r1)into the two-yebonpriequation to solve for the two-yespot or zerorate (z2 ), then set (1 + r1 ) × (1 + breakeven reinvestment rate) = (1 + z2 ) 2 ansolve for the breakeven reinvestment rate. 中文解析本题考察的是计算Implieforwarrates(IFR)。即题干说的观察到市场上现有的一年期(r1)和两年(r2)年期国债的收益率，想确定一年内的盈亏平衡再投资率。考察的公式为基于此公式，只有C描述正确。 为什么不能直接(1+r1)(1+X)=(1+r2)^2?

NO.PZ2021061002000047问题如下 A portfolio manager observes the prianTM of one-ye(r1) antwo-ye( r2) annucoupon government benchmark boncurrently available in the market. How the manager ctermine a breakevenreinvestment rate in one year’s time to help ci whether to invest now forone or two years? A.vi the square root of (1 + r2 ) (1 +r1 ) ansubtra1 to arrive a breakeven reinvestment rate for one yeinone year’s time. B.Set (1 +r1) multiplie1 plus thebreakeven reinvestment rate equto (1 + r2) 2 ansolve for the breakevenreinvestment rate. C.First substitute the one-yerate (r1)into the two-yebonpriequation to solve for the two-yespot or zerorate (z2 ), then set (1 + r1 ) × (1 + breakeven reinvestment rate) = (1 + z2 ) 2 ansolve for the breakeven reinvestment rate. 中文解析本题考察的是计算Implieforwarrates(IFR)。即题干说的观察到市场上现有的一年期(r1)和两年(r2)年期国债的收益率，想确定一年内的盈亏平衡再投资率。考察的公式为基于此公式，只有C描述正确。 题目给出的两年期债券利率难道不是0时间点的利率吗？