สมการ Yt=Y0*e^(-kt)
 

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Graph of Exponential Equation: (Depreciation) y = y0*e^kt.
https://www.youtube.com/watch?v=2NPaZOqgu-M

Problems of Cryobiology - 1991 - Page 34 - Google Books Result
https://books.google.co.th/books?id=e3y6AAAAIAAJ
Magazine
viability of freeze-dried preparations depends on the storage temperature
according to the Arrhenius equation: Yt = Y0'e-Kt, (1) where Yt is the liter of viable cells

Novel Enzyme Technology for Food Applications
https://books.google.co.th/books?isbn=184569371X
R Rastall - 2007 - Technology & Engineering
The reaction degree can be calculated as:
Yt ? Y0 X(%) = ??? × 100 = (1 ? e?kt) *100 Y∞ ? Y0
where X is the reaction degree and Y is the experimental ...

Exponential Growth and Decay - Math is Fun
http://www.mathsisfun.com/algebra/ex...al-growth.html
So we have a generally useful formula: y(t) = a × ekt.
Where y(t) = value at time "t" a = value at the start k = rate of growth (when >0)
or decay (when <0) t = time ...