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44 votes
44 votes
I need help number 5

User Ford Guo
by
2.3k points

1 Answer

14 votes
14 votes

A exponential function is given by:


y=ab^x

y represents the output.

a represents the initial value of the function.

b represents the rate of growth.

x represents the input.

Using the given points:


\begin{gathered} (-2,1.91) \\ 1.91=ab^(-2)_{\text{ }}(1) \\ ------- \\ (-1,2.1) \\ 2.1=ab^(-1)_{\text{ }}(2) \end{gathered}

From (2) solve for b:


b=(a)/(2.1)_{\text{ }}(3)

Replace (3) into (1):


\begin{gathered} 1.91=(a)/(b^2) \\ 1.91b^2=a \\ 1.91((a)/(2.1))^2=a \\ (191)/(441)a^2=a \\ (191)/(441)a=1 \\ a=(441)/(191) \\ \end{gathered}

Replace a into (3):


\begin{gathered} b=(210)/(191) \\ \end{gathered}

a.

b = 210/191

b.


(210)/(191)-1=0.09948

c.


a=(441)/(191)

d.


f(x)=(441)/(191)\cdot((210)/(191))^x

User Stdout
by
2.6k points