Respuesta :
Given
[tex]f(x)=2572e^{0.0359x}[/tex]And x = 0 corresponds to 2004, we can estimate that the year 2008 corresponds to x = 4, then, if we put x = 4 in our function we will have the estimated out-of-pocket household spending on health care in 2008. Therefore
[tex]\begin{gathered} f(4)=2572e^{0.0359\cdot4} \\ \\ f(4)=2572e^{0.1436} \\ \\ f(4)=2969.17401995 \end{gathered}[/tex]If we round it to the nearest dollar we will have
[tex]f(4)=2969[/tex]Final answer:
a) The total expenditures per household in the year 2008 were approximately $2969
For the second item:
Now we have the value of f(x) and we want to find which value of x satisfies the equation:
[tex]2807=2572e^{0.0359x}[/tex]To solve that equation we will need to apply the natural logarithm on both sides and remember that:
[tex]\begin{gathered} \ln (e)=1 \\ \\ \ln (e^x)=x \end{gathered}[/tex]Then, doing the ln both sides we have
[tex]\begin{gathered} \ln (2807)=\ln (2572e^{0.0359x}) \\ \\ \ln (2807)=\ln (2572)+\ln (e^{0.0359x}) \\ \\ \ln (2807)=\ln (2572)+0.0359x\ln (e) \\ \\ \ln (2807)=\ln (2572)+0.0359x \end{gathered}[/tex]Now we have a "linear equation" and we can solve it for x, it will be
[tex]\begin{gathered} \ln (2807)=\ln (2572)+0.0359x \\ \\ 0.0359x=\ln (2807)-\ln (2572) \\ \\ x=\frac{\ln(2807)-\ln(2572)}{0.0359}=2.435\text{ year} \end{gathered}[/tex]Rounding it to the nearest year, it will be 2 years.
Final answer:
During the year 2006 spending reached $2807 per household.