Finding slope and y intercept
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Rick
am 20 Okt. 2014
Kommentiert: Venkata
am 17 Aug. 2016
Hello, I was wondering if there is an easy way to find the slope and intercept of a line using MATLAB, like how it is so easy with Excel where you just plot the data and add a trendline, so then it will tell you the slope and intercept. Here is my code
tau = [15, 38, 100, 300, 1200];
CA = [1.5 1.25 1 0.75 0.5];
CA0 = 2;
dCdt = log((CA-CA0)./tau);
plot(log(CA),log((CA-CA0)./tau))
xlabel('ln(C_{A})')
ylabel('ln(C_{A}-C_{A0}/ \tau)')
I have a theory that says ln((CA-CA0)/tau) = ln(k) + alpha(ln(CA)), and I want to find alpha and ln k, which is my slope and intercept, respectively.
Thank you
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Akzeptierte Antwort
Sean de Wolski
am 20 Okt. 2014
Have you tried the Curve Fitting App (Curve Fitting Toolbox, req'd)
>>cftool
3 Kommentare
Andrew Reibold
am 20 Okt. 2014
If you just use polyfit to get linear data, just take two points from it and do the elementary calculations.
Sean de Wolski
am 20 Okt. 2014
Student Version usually does come with CFT. Try calling:
>>cftool
To see if you do.
Then you can fit arbitrary functions and you don't have to worry about linearizing them to play with polyfit.
Weitere Antworten (2)
Torsten
am 17 Aug. 2016
Did you look at the x-value where your "intercept" is between 0.32 and 0.33 ?
Best wishes
Torsten.
3 Kommentare
Torsten
am 17 Aug. 2016
The p2-value always refers to x=0.
Thus to get the computed value of 0.3046, you must look at the intercept at x=0, not at x=3.85.
Best wishes
Torsten.
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