ttgwd23-3谁给看一下，我就想不明白了

sunnyfields

Alex deposited x dollars into a new account that earned 8 percent annual interest, compounded annually.  One year later Alex deposited an additional x dollars into the account.  If there were no other transactions and if the account contained w dollars at the end of two years, which of the following expresses x in terms of w ?

答案是D  W/1.08+(1.08)^2

 

我觉得是这样算的，不知道哪里错了，算出来不跟答案一样.x的钱存一年后=x(1+0.08)

                                                                       一年以后增加xdollars=x +x(1+0.08)

那么两年以后，就是再过一年，年利率不变的话钱=<x+x(1+0.08)> (1+0.08)=w

                                          那么最后推出x=w/2.08*1.08            

 

谁帮我看看哪里做错了~汗的。。。这道题似乎很简单，没有以前的贴子。。。     

sunnyfields

谢谢楼上的GG，知道了~、

犯懒了，木有多看一眼~

jonathanher

QUOTE:

以下是引用cilia在2007-7-17 13:27:00的发言：

要注意compounded annually

x(1.08)^2+x(1.08)=w

x=w/(1.08^2+1.08)

嗯 关键点那

felicitymq

1.08+(1.08)^2=2.08*1.08&nbsp;

cilia

要注意compounded annually

x(1.08)^2+x(1.08)=w

x=w/(1.08^2+1.08)