[R] Obtain gradient at multiple values for exponential decay model

[g l]

> Sent: Friday, April 06, 2018 at 5:55 AM
> From: "David Winsemius" <dwinsemius using comcast.net>
> 
> 
> Not correct. You already have `predict`. It is capale of using the `newdata` values to do interpolation with the values of the coefficients in the model. See: 
> 
> ?predict
>

The § details did not mention interpolation explicity; thanks.
 
> The original question asked for a derivative (i.e. a "gradient"), but so far it's not clear that you understand the mathematical definiton of that term. We also remain unclear whether this is homework.
> 

The motivation of this post was simple differentiation of a tangent point (dy/dx) manually, then wondering how to re-think in modern-day computing terms. Hence the original question about asking the appropriate functions/syntax to read further ("curiosity"), not the answer (indeed, "homework"). :)

Personal curiosity should be considered "homework".