# Need help with exponential curve

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• May 29th 2011, 10:07 AM
instantaneo
Need help with exponential curve
Year 1950 1960 1970 1980 1990 2000
t 0 10 20 30 40 50
p(t) 69,000 119,594 207,287 359,282 622,726 1,079,342

I already have the average rate of growth from 1970 to 1980 is 15199.5: because p(30)-p(20)/30-20= 359,282-207,287/10=15199.5

I also have the average rate of growth on 1990 to 2000 as 45661.6.

My question is approximating the growth rate of the city in 2000. I tried putting the all the variable in my calculator and did the exponential curve. But, it wasn't right.

The answer for the instantaneous rate of growth is 60,115 (for 2000). I need to know how to get that answer!
• May 29th 2011, 10:53 AM
TKHunny
First, please fix confusing notation. This is no good: "p(30)-p(20)/30-20". It should be [p(30)-p(20)]/[30-20] - or some other grouping symbol indicating actual intent.

Hint:

119594/69000 = 1.733246
207287/119594 = 1.733256
359282/207287 = 1.733259
622726/359282 = 1.733251
1079342/622726 = 1.733253

I would guess it has something to do with 1.733-ish.