Answer:
(a) >0;<0
Step-by-step explanation:
We are given that an exponential function
[tex]A=A_0e^{kt}[/tex]
We have to find the correct answer.
Differentiate w.r.t t
[tex]\frac{dA}{dt}=kA_0e^{kt}[/tex]
If k is positive
i.e k>0
Then, [tex]\frac{dA}{dt}=Positive >0[/tex]
Hence, the function is increasing.
When k is negative
i.e k<0
Then,[tex]\frac{dA}{dt}=negative<0[/tex]
Hence, the function is decreasing.
If k>0 the functions models amount or size of a growing entity if k<0 the models amount size of a decaying entity.
Option (a) is true.