where t=0 corresponds to 1962.
data:
year t C
----------------
1962 0 319
1982 20 340
2002 40 368
(a) determine the coefficients a, b, and c and write the equation
Equations:
[1]
[2]
[3]
[4] (from [1] and [2])
[5] (from [1] and [3]
[6] ([4], doubled)
([5]-[6])
[7]
(from [5] and [7])
ANSWERS:
a = 7/800
b =7/8
c = 319
(b) Find the year when C = 2(319) = 638
Solving algebraically is certainly possible, but very tedious.
Graph the function and the constant 638 on a graphing calculator and find where they intersect.
A graph:
The intersection of the two graphs, to the nearest whole number, is 147, indicating the year 1962+147 = 2109.
ANSWER: year 2109