How to find tangent line of curve

Hi, I'm completely new to matlab and I have a dataset of time and temperature. I want to apply the Ziegler–Nichols method to this data. For this, I want to pass a tangent line passing through the inflection point, how can I do it? Thank you in advance for all your answers. Attached are data as excel file and txt file.

[Rik]

Have a read here and here. It will greatly improve your chances of getting an answer.

What have you tried so far?

Or are you going to delete this question as well without responding?

Answer 1

[Star Strider]

See: How to draw a tangent line on a curve

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