这道微积分的题目怎么写?只给答案也可以.

题目

这道微积分的题目怎么写?只给答案也可以.
A certain motorcycle manufacturer has been building motorcycles for 99 years. Over that period, production has increased steadily at an annual rate of 5%, so that the production rate, in motorcycles/year, after t years was
r(t)=A⋅1.05t
where A is a constant representing the initial production rate. What fraction of their total production was built during the last 12 years? Your answer should be a number between 0 and 1.
中文大概意思就是：一家摩托生产商生产摩托车生产了99年，产量以每年5%增长。所以增长率是r(t)=A⋅1.05^t每年 t是年数 A是常数
然后要找最后12年的总产量的分数 答案在0到1之间。
式子里面应该是1.05的t次方 打错了。

答案