# Another Algebra II Question

• Jul 30th 2008, 04:09 PM
ep78
Another Algebra II Question
So, you have this....
-470001t(squared)+4110992t+14032612/-469.4t(squared)+3745t+19774 (sorry don't know how to square them)

and then it asks..Find the year in which the average benefit was $800.00 In order to graph this on my calculator i have to put certain numbers in the "Window" button, and i just can't figure out what numbers to put in... -Thanks • Jul 30th 2008, 04:25 PM topsquark Quote: Originally Posted by ep78 So, you have this.... -470001t(squared)+4110992t+14032612/-469.4t(squared)+3745t+19774 (sorry don't know how to square them) and then it asks..Find the year in which the average benefit was$800.00

In order to graph this on my calculator i have to put certain numbers in the "Window" button, and i just can't figure out what numbers to put in...

-Thanks

Ummm.... I presume the formula you gave is for the average benefit? If so then you are looking for x values such that the y values are close to 800. What I'd do is a search. You know that the year, x, is positive, so set the x part of the window to something like 0 to 100. Set the y to 700 to 900. If the function does not show up in this box, use 100 to 200 for x in the next window, etc. When the function shows up in the window you can zoom in on this a bit by estimating the correct range of values for x and y from where the function is in the window.

That or you can graph the function
$\frac{-470001t^2+4110992t+14032612}{-469.4t^2+3745t+19774} - 800$
and have the calculator search for the zeros. That will give you a good idea how to set your graphing window.

By the way, please use parenthesis. The expression you wrote is
$-470001t^2+4110992t+ \frac{14032612}{-469.4t^2}+3745t+19774$
not the similar expression I wrote above.

-Dan