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Offline engineering student  
#1 Posted : 28 November 2019 00:04:57(UTC)
engineering student

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hi i have a table of values [R(t=60)=50965] with no obvious pattern and i need to create a function to fit into the formula
1/T = d (ln(R(t)) / dt
my thought was to make S(t)=ln(R(t)) and do d(S(t))/dt but i dont know how to turn a bunch of values into a function in smath and excel doesnt understand the function properly (i left out the last value and did auto complete and it was too far off)
HW8_Table.PNG

R(t) is in counts per second
and i am solving for T

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Offline engineering student  
#2 Posted : 28 November 2019 00:30:00(UTC)
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Originally Posted by: Jean Giraud Go to Quoted Post
Originally Posted by: engineering student Go to Quoted Post
hi i have a table of values [R(t=60)=50965] with no obvious pattern and i need to create a function to fit into the formula
1/T = d (ln(R(t)) / dt

Start by creating the Smath data table, attach in the Forum.
Your wording looks very alike fitting the laser project.
Toke > 1 month to do in Mathcad as it was so unusual.
But we had lot more data points.
Jean


HW8Q1.sm (3kb) downloaded 13 time(s).

do you mean like a matrix?
Offline Jean Giraud  
#3 Posted : 28 November 2019 01:01:34(UTC)
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Originally Posted by: Jean Giraud Go to Quoted Post
Start by creating the Smath data table,

Before going ahead, the wiggling around the straight fit,
is it real or digitizing noise from equipment ?

Data.PNG
Offline Jean Giraud  
#4 Posted : 28 November 2019 01:08:22(UTC)
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Data.sm (29kb) downloaded 13 time(s).
Offline engineering student  
#5 Posted : 28 November 2019 01:08:35(UTC)
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Originally Posted by: Jean Giraud Go to Quoted Post
Originally Posted by: Jean Giraud Go to Quoted Post
Start by creating the Smath data table,

Before going ahead, the wiggling around the straight fit,
is it real or digitizing noise from equipment ?

Data.PNG


i would be comfortable assuming it is based on the contextHW8_Table.PNG PNR HW 8 Fall 2019.pdf (309kb) downloaded 8 time(s).
Offline Jean Giraud  
#6 Posted : 28 November 2019 03:14:47(UTC)
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... in your original scale XY.

Data.sm (41kb) downloaded 13 time(s).
Offline engineering student  
#7 Posted : 28 November 2019 04:14:46(UTC)
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thank you so much
as much as i would like to say part b of the question i need to do my own homework i just couldnt understand how to get the equation of that line

thanks again
Offline Jean Giraud  
#8 Posted : 28 November 2019 06:03:25(UTC)
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Originally Posted by: engineering student Go to Quoted Post
thank you so much
as much as I would like to say part b of the question I need to do my own homework I just couldn't understand how to get the equation of that line

1. You mean equation of the straight red line of the first plot ?
2. Or: the piece wise linterp between the support points ?
linterp, cinterp, ainterp are built-in Smath from f(x) menu.
The straight line in [1] can be manipulated a bit from statistical methods [Not Smath built-in].
Also, if you don't like the rough bifurcation at the supports
points, easy to fillet for smooth path.
No more need for the first replies before the last attachment,
then will be removed.

Cheers ... Jean

Offline CBG  
#9 Posted : 28 November 2019 07:35:47(UTC)
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I think you can also use the least-squares method to find the equation that best fits your data.

LSM_Eng_Stud.png

Ajust_by_Last_Square_Selection_Engineering_studente.sm (63kb) downloaded 20 time(s).


Best Regards

Carlos
thanks 1 user thanked CBG for this useful post.
on 28/11/2019(UTC)
Offline Jean Giraud  
#10 Posted : 28 November 2019 14:55:51(UTC)
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Here is Cholesky [Least Squares], otherwise.
Ge sensor [Germanium] is an exceptional application.
Jean

Cholesky.PNG

Genfit 0 Ge SubCryogenic.sm (40kb) downloaded 16 time(s).
Data.sm (55kb) downloaded 12 time(s).
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