Mike,
I tried charting y-range and LN(x-range). It is not linear, but is still log
shaped (concave downward), though not as much as the original chart of
x-range,y-range. It doesn't make sense to me to calculate LINEST on this data
which is not linear. I'm just not getting this yet.
Art

"Mike Middleton" wrote:

"Tushar's web site shows how to get the same results using =LINEST(y-range,
LN(x-range))".

- Mike
www.mikemiddleton.com

"ArthurJ" wrote in message
...
Thank you Tushar. I did look at your reference materials, and learned a
lot.
However, I still do not see how to use LINEST to derive the coefficients
of a
logarithmic trendline. LINEST is for linear trends only, correct?

Let me clarify my problem. On my chart I have a log trendline that
displays
as:
y = 88.28Ln(x) - 38.613. It has a very good fit (r sqared of .97).

I am looking for a function (or some method) of returning the coefficient
values of 88.28 and -38.613 so that I can use them in subsequent
calculations.

Thanks,
Art

"Tushar Mehta" wrote:

To use the LINEST function for the coefficients of a log trendline see
Trendline coefficients
http://www.tushar-mehta.com/excel/ti...efficients.htm

--
Regards,

Tushar Mehta
www.tushar-mehta.com
Excel, PowerPoint, and VBA add-ins, tutorials
Custom MS Office productivity solutions

In article ,
says...
I have been using the trendline - logarithmic type - on some charts.
Although
the equation in the form
y = a*ln(x) + b
can be made visible on the chart, I need a function that will return
the a
and b coefficients.

I can't find such a function. I don't think logest is the same.

Art