英文数学题,指数函数, excel 表格 （求解!急!）

英文数学题,指数函数, excel 表格 （求解!急!）
The table below gives the number of text messages (in billions) for selected years.








Year


 



Number of Text Messages
(in billions)


 





2003 2.1
-----------------





2004 4.7


----------------





2005 9.8


------------------ -





2006 18.7


-----------------





2007 48.1


---------------------





2008 110.4


 






(A) Follow the directions above to find an exponential model, N(t), that predicts the number of
text messages (in billions) t years after 2000. Give the equation in both forms discussed in
class. What is the annual rate of increase? What is the continuous annual rate of increase?[Regression

For each set of data use a spreadsheet program like Excel to make a scatter plot. Make a title.
Label the axes with numbers and what they represent. Include units.
If using Excel choose "Design" then “Chart Layouts” to type in the labels.

Find the equation of the model with the spreadsheet program: graph the model and have the
formula on the graph. Excel calls the regression model a “trend line”. On Excel make the
scatterplot, then go to “Layout”, and then “Trendlines”, choose “More Trendline Options...” and
look for the type of function you want. Be sure to click the box on the bottom that says “Display
Equation on Chart”














Use the model to answer the questions associated with each set of data. ]
自己做出来的：(A)公式1：y=0.1956*2.1898^x 公式2：y=0.1956e^0.7838x



不知道对不对.

用excel散点图(scatterplot),找到趋势线(Trendlines),选择指数(exponential model),得出指数方程y = 0.9975 e^0.7838(x - 2002).
2000年的annual rate,用线性求值,（这对于我来说难啊.所以采用了2003年和2004年的数据）得出,当年的增长率是2.6
continuous rate就是方程中x的系数了