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What does the constant 0.4 reveal about the rate of change of the quantity?

What does the constant 0.4 reveal about the rate of change of the quantity?-example-1
What does the constant 0.4 reveal about the rate of change of the quantity?-example-1
What does the constant 0.4 reveal about the rate of change of the quantity?-example-2
What does the constant 0.4 reveal about the rate of change of the quantity?-example-3
User Jemil Riahi
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1 Answer

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In general, the exponential growth/decay formula is


\begin{gathered} g(x)=a(1+r)^(kx) \\ a\rightarrow\text{ intial amount} \\ r\rightarrow\text{ growth/decay} \\ k\rightarrow\text{ constant} \\ \end{gathered}

If 1+r>1, the function is growing while 1+r<1 implies that it is decaying.

In our case,


\begin{gathered} f(t)=870(0.4)^(24t) \\ \Rightarrow(1+r)=0.4<1 \\ \Rightarrow f(t)\text{ is decaying} \end{gathered}

Furthermore,


\begin{gathered} 1+r=0.4 \\ \Rightarrow r=-0.6=-60\% \end{gathered}

Thus, the function is decaying exponentially at a rate of 60%.

Finally, notice that t stands for the number of days; therefore, 24t implies that the function exponentially decays 60% a total of 24 times per day, and 24 times per day is equivalent to 1 time every hour.

Hence, the function decays 60% every hour.

User Bazley
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