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Question

Andrew measures the amount of a very unstable substance to be 100 moles. The half-life of this substance is 3 days (after 3 days, half is gone).

 

write an exponential function that models this situation where Y is the amount of substance and X is time in days.

Answer 1

f(x) = ab^x, where a = starting amount, b = rate of change, x = time.

 

50 = 100b³

0.5 = b³

(0.5)^1/3 = b

 

y = a((0.5)^1/3)^x

y = 0.5^x/3a