Find maximum of exponential equation created with CFTOOL?

4 次查看（过去 30 天）
Per
Per 2011-4-18
Hello!
I need to find the maximum point of my data that i've extrapolated fitting it to an exponential-equation created by CFTOOL. Where y goes to infinity (I could also flip the data if it makes it easier). How can I do this the easiest way?
My graph: http://i53.tinypic.com/rumsr7.png

请先登录，再回答此问题。

回答（2 个）

Paulo Silva
Paulo Silva 2011-4-18
y(end) %this should give you the maximum value of y
max(y) %another way
  1 个评论
Per
Per 2011-4-18
Thanks. But this only gives me values I already know and does not forecast the stable temperature (sorry for not specifying this earlier)

请先登录，再进行评论。

John D'Errico
John D'Errico 2011-4-18
Are you looking for that value of x where your model would predict an infinite value? Sorry, but IF this is an exponential model, it NEVER reaches infinity.
The fact is, extrapolation of data to an asymptote at infinity is a perilous task. The specific model you choose will be the driver here, and you have not bothered to tell us that information.
Had you chosen a model that makes mechanistic, physical sense in the context of the physical system you are trying to model, this would be a bit different. But we have no indication this is true.
  1 个评论
Per
Per 2011-4-18
Thank you John. I needed that reminder. My knowledge in math is really not that great.
The data I have is temperature (x) vs. time (y), since temperature decay is (approx.) an exponential function, i just assumed i could try to use an exponential regression line to fit my data to, to "forecast" the stabilized temperature.
The measured temperature is thus stable, and the thermometer is adjusting to this new temperature. I want to find the actual temperature.

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 Least Squares 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by