02-28-2017 01:52 AM
I have data as shown below.
I would like to use Labview to get the tangent in the point where Y =2.
Is there any way to do this?
Solved! Go to Solution.
02-28-2017 03:10 AM - edited 02-28-2017 03:24 AM
edit: i made a mistake, just swap the X_0 and Y_0 !
EDIT2: so to clarify:
Using LabVIEW, you can get the coefficients, and also can get the coefficients for the derivative. After that just simple math to find tangent at a certain point.
02-28-2017 03:18 AM
Or you try one of the Derivate functions and they should give you a good approximation, if it's only the answer you're after.
/Y
02-28-2017 04:33 AM
Actually, the only data I’m interested in, is the slope of the tangent in this point.
In order to get the fit, I used exponential fit, hoping I would get the expression of the curve as I did it in the in excel (image).
The derivation function you talked about, where do I find it, and how to use it?
02-28-2017 05:34 AM
Derivative x(t) under mathematics ==> Integration & differentiation.
I haven't tried it, but the help and the linked example (in the help) looks good.
/Y
02-28-2017 10:55 AM - edited 02-28-2017 11:15 AM
The exponential fit outputs the "amplitude" and "damping" (and "offset", but you currently force the offset to be zero). These are the two parameters that define the best fit and you can analytically calculate the derivative instantly for any desired X. This is the correct way.
(Doing numerical methods, such as the mentioned derivative function will not give you anything accurate)
03-01-2017 09:01 AM
Hi Blokk
Thank you for your very fine explanation
Using your calculation of the tangent seems to give at wrong result ?
Are you sure the derivative is correct ?
I get the derivative: a*b*exp(b*x). Don’t know if that correct?
03-01-2017 09:59 AM
Michael.Koppelgaard wrote:I get the derivative: a*b*exp(b*x).
That's what wolfram alpha says. 😉
03-01-2017 10:02 AM
That is correct, the division was my mistake. When you derivate this, you need to multiply with the derivative of the internal function.
03-01-2017 10:20 AM - edited 03-01-2017 10:20 AM