Trendline and its referencing / linking to a cell

-----Original Message-----
PLEASE HELP

I have not been able to receive help. Probably the
question may not be
clear. I am once again putting up the question in detail
for your
help.

I am trying to create a chart and trendline for a data
set to be used
for interpolation/forecasting. The data is for Rel.
humid. (Relative
Humidity) and Power Output (PO) for different ambient
Temperatures. I
have data available for Power Output for 0 to 100 Rel.
Humid. values
(in step of 10) for four different ambient temperatures
viz. 0, 15, 30
and 45 deg c.

PLEASE NOTE THAT POWER OUTPUT (PO) DEPENDS BOTH ON
HUMIDITY AND AMBIENT
TEMPERATURE.

Problem is find out Power Output for different rel.
humid. values (for
any value between 0 to 100) and for different amb. temp.
(any value
between 0 to 45 deg c.)

Following is the data set:

X-axis Y-axis ------------
Rel PO PO PO PO
Humid @0deg @15deg @30deg @45deg
0 1.0000 1.2 1.4 2
10 1.1000 1.4 1.48 2.2
20 1.2000 1.6 1.56 2.4
30 1.3300 1.8 1.64 2.6
40 1.4600 2 1.72 2.8
50 1.5900 2.2 1.8 3
60 1.7200 2.4 1.88 3.2
70 1.8500 2.6 1.96 3.4
80 1.9800 2.8 2.04 3.6
90 2.1100 3 2.12 3.8
100 2.2400 3.2 2.2 4

I tried to attempt above problem by plotting graph
between Rel. Humid.
on X axis and Power Output (PO) for four ambient
temperature on Y axis.
By doing above I have been able to plot four curves.

I have been able to automatically generate trendline for
Power Output
(PO) for any input value of ambient temperature between 0
to 45 deg. c.


However, I am unable to link the automatically generated
trendline
equation to a cell wherein it automatically gives result
for any input
value of Rel. Humidity.

You may suggest any better method to solve above problem.

Other related problems are :

1) How to create a 3-D chart with above data set. Means
Whether it is
possible from EXCEL to obtain trendline equation for two
input
variables.

Presently we get equation in form of y=f(x), but whether
it is possible
to get in form of z=f(x,y).

2) Is there any way to link the trendline equation to a
set of input
data and automate the process.

Thanking you in anticipation of reply
Sudhanshu


---
Message posted from http://www.ExcelForum.com/

from the add trendline box choose option "display
equation" then drag the left clicked mouse over the entire
equation. edit copy and paste into a cell. It's text so
you have to change the "x" for *your cell^ (eg *AE53^).
You can do it manually of using "edit find replace" but
that leaves a ^ at the end. Then delete the "y" and it
should work. Be careful unless you chooose a polynomial
with a high order (I always choose the max of 6) and
format the equation text box to "number" 10 decimal
points, otherwise you end up with an equation that doesn't
track youe data.

Mike