"each graph represents a correspondence between x and y. tell whether the correspendence is a function. if it is, give its domain and range."
http://img353.imageshack.us/img353/1014/functionnb8.jpg
2007-01-12 06:36:09 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
its one of the questions on my hw that i dont understand. how do you figure out the domain/range of a function on a graph?
2007-01-12 06:39:08 · update #1
The domain is the values of x that the function can take. In your graph x can take any value from -infinity to infinity. The range is the values y takes. In your graph, y goes from -something to infinity. A correspondence between x and y is a function when there is only one value of y for each value of x
2007-01-12 06:45:09 · answer #1 · answered by ENA 2 · 0⤊ 0⤋
Ok dont worry. Domain is all the possible "input" values. For example in f(x)=10/x, the input cant be x as it ends up being 10/0 which isnt possible.
Range is the value of output that can be made from the function, e.g. in f(x)=x^2 t, the range is all positive numbers (as any number + or - squared is always positive. The best thing to do is find the function and then figure out the domain and range. In domain look for dividing by 0 or negative roots, and in range look for what values ^2... can take.
As to your graph picture, well the domain can be anything: you can take any value on x and it will give something on the graph. But the range(output) cant be less than the bottom of the graph on y. (For example if the graph crosses with the y axis at -7 on y, then the range of f(x) ie the answer on the y axis cant be -8, as the graph doesnt go there.
I know this is a bit :S but I hope it makes a bit of sense
2007-01-12 14:58:22 · answer #2 · answered by ღ♥ღ latoya 4 · 0⤊ 0⤋
you just gotta know your parabolas (parabolae?). This looks like a simple quadratic. plug in x = 0, and you've got the lower bound of your range. That's the lowest that y will ever achieve (try it yourself, try to find a value of x that gets you a lower value of y. you can't, because if you square something it can't ever be smaller than 0). All of the other values (upper bound, lower bound of domain, and upper bound of range) are all infinite. You can keep plugging away numbers until you die, and the values will just get bigger and bigger.
2007-01-12 14:52:24 · answer #3 · answered by John C 4 · 0⤊ 0⤋
Homework?
.....
2007-01-12 14:38:17 · answer #4 · answered by god knows and sees else Yahoo 6 · 0⤊ 0⤋
what the?
2007-01-12 14:38:05 · answer #5 · answered by Anonymous · 0⤊ 0⤋