100/(1+r)+1000/(1+r)2=1100求R是多少?

Question

100/(1+r)+1000/(1+r)2=1100 求R是多少?

Answer 1

令a=1+r
两边除以100
1/a+10/a²=11
两边乘a²
11a²-a-10=0
(11a+10)(a-1)=0
a=-1/10,a=1
a=1+r
r=a-1
所以r=-11/10,r=0