问一道题：NO.PZ2016070201000065

$0.89000 > $0.80000. $0.94340 > $0.89031. $0.94373 > $0.94340 The left-hansi of Jensen’s inequality is the expectepriin one yeusing the 1-yespot rates of 8% an4% E[$1(1+r)]=0.5×$1(1.08)+0.5×$1(1.04)=0.5×0.92593+0.5×0.96154=$0.94373E{\lbrack\frac{\$1}{(1+r)}\rbrack}=0.5\times\frac{\$1}{(1.08)}+0.5\times\frac{\$1}{(1.04)}=0.5\times0.92593+0.5\times0.96154=\$0.94373E[(1+r)$1​]=0.5×(1.08)$1​+0.5×(1.04)$1​=0.5×0.92593+0.5×0.96154=$0.94373 The expectepriin one yeusing expecterate of 6% computes the right-hansi of the inequality as: $10.5×1.08+0.5×1.04=$11.06=0.94340\frac{\$1}{0.5\times1.08+0.5\times1.04}=\frac{\$1}{1.06}=0.943400.5×1.08+0.5×1.04$1​=1.06$1​=0.94340 Next, vi easi of the equation 1.06 to scount the expecte1-yezero-coupon bonprifor one more ye6%. The priof the 2-yezero-coupon bonequals $0.89031 (calculate$0.94373 / 1.06), whiis greater th$0.89000 (the priof a 2-yezero-coupon bonscountefor two years the expecterate of 6%). Thus, Jensen’s inequality reveals th$0.89031 > $0.89000 题目能做正确，但是我是算除了0.89031这个书，再联想convexy涨多跌少的性质会使得实际债权价格更大才选正确A的，讲课的时候有提到Jensen’s ineuality这个知识点么？似乎没有印象了，如果讲义上有，麻烦告知一下在那一页，谢谢！