年金现值转换疑问例子：比如你在银行里面年末存入1200元,年利率是10%的话,你这5年所存入资金的现值=1200/(1+10%)+1200/(1+10%)^2+1200/(1+10%)^3+1200/(1+10%)^4+1200/(1+10%)^5=1200*[1-(1+10%)^-5]/10%请问为什么1

　　年金现值转换疑问

　　例子：比如你在银行里面年末存入1200元,年利率是10%的话,你这5年所存入资金的现值=1200/(1+10%)+1200/(1+10%)^2+1200/(1+10%)^3+1200/(1+10%)^4+1200/(1+10%)^5=1200*[1-(1+10%)^-5]/10%请问为什么1200/(1+10%)+1200/(1+10%)^2+1200/(1+10%)^3+1200/(1+10%)^4+1200/(1+10%)^5可以转换为1200*[1-(1+10%)^-5]/10%呢?