I know this has got to be really easy but I'm on summer vacation and I'm blanking-
If a service charges
$15 for 30min and
$25 for 1 hour
What is a function of time that will give me those values and everything inbetween?
Convert the second point from "hours" to "minutes", so you have the same units.
Then use the fact that they've given you two points in the form (x, y) = (minutes, cost), along with the formula for slope to find the slope of the line through these two points.
Then take one of the points (it doesn't matter which) and the slope you just found, and plug them into one of the straight-line formulas, such as the point-slope formula, to find the equation of the straight line through these two points.
If you get stuck, please reply showing how far you have gotten. Thank you!
Not quite sure what you're asking, but...
This is a stepwise function, meaning that everytime a customer exceeds the time limit he/she has to pay for an additional time period even if only for a moment.
These functions are denoted by
$\displaystyle C(t)=[[t]]$
http://www.ehow.com/video_4756977_us...-function.html
In your original post, it was implied that the charges were to be by the half hour, or by the hour respectively. In most real world applications (Eg: postage, rentals, etc.) this means that there are no "in between" charges. You either pay for an hour (or half-hour) or nothing at all. If this is the case, see my last post and then tell me if there is something that you do not understand. If it is not the case, again, tell me and I will adjust my approach accordingly.
Consult this page Online Graphing Calculators: WebGraphing.com
Familiarize yourself with regression, and you should be all set.
Next time, Express exacly what is that you need help with. Every one here has tried as hard as they can to help you. If you'd like to improve your chances of getting the help that you need, start clicking the "thanks" button, instead of overheating.
Well, which one did you want? A quadratic, an exponential, or something else?
We can't see the data you're looking at, and we can't know the patterns you have or need. There are infinitely-many equations which can be put through the listed points (two originally, and now three). You'll need to specify what you're expected to find, what techniques you've been directed to use, and where you're getting stuck.
Thank you!