Project exponential growth againt linear timeline

Hi,

I have a series of values growing exponentially over time. I'd like to
project the values in the next 5 years, but I can't figure out how to
use the related functions. For instance:

A B
1 2001 2
2 2002 4
3 2003 8
4 2004 16
5 2005 32
6 2006
7 2007
8 2008
9 2009
10 2010

Now, I want to find the function that will yield the series {64, 128,
258, 512, 1024} in cells B6:B10.

For cell B6 (2006):
- TREND(B1:B5;A1:A5;A6) will not result in 64, which is to be expected
since it's not a linear growth;
- GROWTH(B1:B5;A1:A5;A6) does not work at all and returns an error
(#NUM!). It seems that the series in column A should also be
exponential for GROWTH to work. But time is not exponential (luckily).

So which function should I use to project an exponential progression on
the Y axis, along a linear progression (time) in the X axis? If I use
the "Add trendline" in the graph, it does work, by I can't find a way
to get the actual figures.

Thanks in advance for the help.

Kind regards,

Raph

Right-click on trendline==>Format Trendline==>Options==>Display equation on
chart

In your specific example, =POWER(2,(year-2000)) gives results you require

HTH

"[email protected]" wrote:

> Hi,
>
> I have a series of values growing exponentially over time. I'd like to
> project the values in the next 5 years, but I can't figure out how to
> use the related functions. For instance:
>
> A B
> 1 2001 2
> 2 2002 4
> 3 2003 8
> 4 2004 16
> 5 2005 32
> 6 2006
> 7 2007
> 8 2008
> 9 2009
> 10 2010
>
> Now, I want to find the function that will yield the series {64, 128,
> 258, 512, 1024} in cells B6:B10.
>
> For cell B6 (2006):
> - TREND(B1:B5;A1:A5;A6) will not result in 64, which is to be expected
> since it's not a linear growth;
> - GROWTH(B1:B5;A1:A5;A6) does not work at all and returns an error
> (#NUM!). It seems that the series in column A should also be
> exponential for GROWTH to work. But time is not exponential (luckily).
>
> So which function should I use to project an exponential progression on
> the Y axis, along a linear progression (time) in the X axis? If I use
> the "Add trendline" in the graph, it does work, by I can't find a way
> to get the actual figures.
>
> Thanks in advance for the help.
>
> Kind regards,
>
> Raph
>
>

Toppers a =E9crit :

> Right-click on trendline=3D=3D>Format Trendline=3D=3D>Options=3D=3D>Displ=
ay equation on
> chart
>
> In your specific example, =3DPOWER(2,(year-2000)) gives results you requi=
re

Thanks. In my real-life instance, the displayed equation is "y =3D
6105.6e0.6015x", so I'm not really sure what I'm supposed to do with
it. I thought the value (y) for any given year (x) would be:

=3D6105.6*EXP(0.6015*(year-2000))

But it doesn't match the graph.

Raph

For your original data my equation was y=e0.6931x (=EXP(0.6931*(A1-2000))
which gave the following results for 2001- 2010:

1.999905641
3.999622573
7.998867747
15.99698073
31.992452
63.98188523
127.9577332
255.9033924
511.7826381
1023.516985

Do you want post your real-life table and I'll give it a try?


"mrgou" wrote:

>
> Toppers a écrit :
>
> > Right-click on trendline==>Format Trendline==>Options==>Display equation on
> > chart
> >
> > In your specific example, =POWER(2,(year-2000)) gives results you require
>
> Thanks. In my real-life instance, the displayed equation is "y =
> 6105.6e0.6015x", so I'm not really sure what I'm supposed to do with
> it. I thought the value (y) for any given year (x) would be:
>
> =6105.6*EXP(0.6015*(year-2000))
>
> But it doesn't match the graph.
>
> Raph
>
>