假设你现在投资10000块钱,回报率为4%每年,你将会有多少钱在2年以后.（是英文翻译的,意思大致就是这个）.然后连续复

假设你现在投资10000块钱,回报率为4%每年,你将会有多少钱在2年以后.（是英文翻译的,意思大致就是这个）.然后连续复利率 我列出了式子 10000*e^0.04*2 后面一问我就不会了.how fast is your money growing (in units of dollars per year) at the moment of your initial investment?答案是4000.我不知道怎么来的.还有一问是how fast is your money growing (in units of dollars per year) after two years?答案是400*e^0.08
希望高手可以帮我解答下,为什么是这2个答案,是怎么求出来的?
原题是：Suppose that you invest $10,000 at an interest rate of 4% per year.How much money would you have after two years.
第一问 if it is compounded annually?__________
第二问 if it is compounded every 3 months?_________
if it is compounded continuously?_________
Assume that you are in the situation of above problem and that the interest is compounded continuously.
2.how fast is your money growing (in units of dollars per year) at the moment of your initial investment?
3.how fast is your money growing (in units of dollars per year) after two years?