Question 971418: So I've been doing this question, but after some thinking im pretty sure I'm not on the right track.
1) Suppose in cells A1 and A2 of a spreadsheet, you have the GDP figures for months of January and February of a given country in a given year. What is the formula you need to put in cell A3 to obtain the estimated GDP figure for the month of March so that the GDP gures all lie on the same line? Hint:What is the 3rd y-coordinate in terms of A1 and A2 (i.e. linearly extrapolate the GDP gures for January and February to the month of March).
I think its just A1+A2...but maybe I have to find the equation of the line....Im not too sure and I have no clue where to begin.
Found 2 solutions by rothauserc, Theo:
Answer by rothauserc(4718)   (Show Source):
You can put this solution on YOUR website! you need the equation of the line, use point - slope form
y = mx + b where m is the slope and b is the y intercept, let the x axis be the months 1, 2, 3, .... in the given year, then
m = (february GDP - january GDP) / (2 - 1)
then substitute a point (you can use either point) to determine b
therefore you have the equation of the line which you can use to predict any GDP for a given month.
Answer by Theo(13342)  (Show Source):
You can put this solution on YOUR website! it's actually A2 plus (A2 minus A1).
you would find the difference between A1 and A2 and then add that to the value that's in A2 in order to get the value that's in A3.
that would make the differnece linear, i.e. an arithmetic progression.
for A4, youwould use A3 plus (A3 minus A2).
you would get the same common d9ifference.
for example:
A1 = 5
A2 = 10
A3 = A2 + (A2 - A1) = 10 + (10-5) = 10 + 5 = 15
A4 = A3 + (A3 - A2) = 15 + (15-10) = 15 + 5 = 20
etc.
you would have:
A1 = 5
A2 = 10
A3 = 15
A4 = 20
etc.
|
|
|
