J-F Neron (jfneron at fse.ulaval.ca) wrote:
>Is it possible to measure the area under the curve with excel or with some
>MACINTOSH shareware.
>This is a example of the data:
>Time TG
>-15 80
>0 85
>5 220
>10 210
>15 200
....
There are a number of numerical integration techniques that would allow
you to do this and could be adapted to a spreadsheet. The simplest is
referred to as the Trapezoid Rule (may also be referred to as Eulers Method
in some books) which calculates the area of a trapezoid bounded by
adjacent sampling points:
sum across sampling intervals Area= 1/2*[TG(i-1) - TG(i)]*[t(i-1) - t(i)]
A more accurate and and slightly more complex method is Simpsons Rule
which fits a parabolic curve across three adjacent points (Best to cruise
through a Calculus text to get this one).
Also there are the Runge-Kutta algorithms but I don't think these will
readilty conform to a spreadsheet.
Hope this helps
--------------------------------------------------------------------------
David Kirschtel |
Dept. of Botany | What if the 'invisible hand' is
Univ. of Vermont |
Burlington, VT 05405-0086 | guided by myopic eyes.
|
tel 802.656.0429 |
email dkirscht at moose.uvm.edu |
