Plotting trendline for select data points, not entire data set.

[Prometheus03]

Hey all,

Im trying to plot some graphs of chemical reactions, and i need to get the slope of the line of the initial reaction, before it slows down. This is the first 3 or 4 points of the data set. However when i plot the trendline, it does the entire data set and not just the first few points.
Is there anyway to get excel to trendline the first few data points, or is there anyway i can manually select the points i want trendlined?
It seems like a really obvious thing that microsoft has overlooked...
I don't mind if i have to download add-ons or anything to make this possible.

Thanks in advance for any help!

 

[Robert Mika]

Hi Prometheus03 and welcome to the board:
Look here:
http://www.excelforum.com/excel-charting/657512-partial-trend-line.html
or here

http://www.pcreview.co.uk/forums/plotting-partial-trendline-t1785107.html