# Polynomial and Rational Functions

#### arl2267

##### New member
For the years 1998-2009, the number of applicants to US medical schools can be closely approximated by:

A(t)= -6.7615t4+114.87t3-240.1t3-2129t2+40,966

where t is the number of years since 1998.

a) graph the number of applicants on 0<= t <= 11

b) based on the graph in part a, during what years did the number of medical school applicants increase?

If someone could explain to me how to enter the equation into a TI-84 that would be helpful. I know that you go to Y= and then enter in the equation, I get stuck on what to do after that. If I hit the graph button I don't see the full graph. How should I adjust the "window" values in order to see what the graph should look like? Thanks.

#### Ackbach

##### Indicium Physicus
Staff member
TI calculators generally understand implied multiplication. So you could enter this:

-6.7615x^4+114.87x^3-240.1x^3-2129x^2+40966

Note that I've changed the t's to x's - TI's sometimes prefer x as the independent variable. Also note the use of the "^" key, I think right above the "$\div$" key, at least if this manual is the correct guide to your calculator.

As for seeing the whole graph, you'll need to keep increasing the y limits in your viewing window until you see the whole graph.

Are you sure you've typed up the function correctly? There are two cubic terms, and no linear term. That looks fishy to me, as does the plot of this function. There can't be negative applicants to medical school!