Answers:
- Relation
- Domain
- Range
- Function
- Vertical Line Test
- Function Notation
- Practical Domain
- Practical Range
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Step-by-step explanation:
- A relation is basically anything where we connect one variable to another. Usually there are math operations involved to have a predictable rule. For example, y = x+5 says "add 5 to the x input to get the y output". But we won't always have a rule like this to connect x and y.
- The domain is the set of allowed inputs (x values). For example, if we had the function y = 1/x, then we can plug in anything but x = 0. This is to avoid a division by zero error.
- The range is the set of allowed output y values. You can use a graph to determine the range, or find the domain of the inverse (assuming one exists).
- This is basically saying each input goes to exactly one output only. If such a thing happens, then the relation is a function.
- A visual way to test if you have a function is to use the vertical line test. If you can pass a vertical line through more than one point, then it is said to have failed the vertical line test and we don't have a function. Failing the vertical line test shows that a particular x value leads to multiple y outputs.
- Function notation is when we replace y with something like f(x) so the function name is a bit more descriptive.
- Let's say we had the function f(x) = 100/x. The x represents the number of people, and f(x) is the average cost per person. Before I mentioned that the domain is anything but 0, to avoid a division by zero error. Realistically, we also would make x the set of positive whole numbers (1,2,3,4,...) since x is the number of people. This is one example where a theoretical domain shrinks down to a more practical one.
- Since the domain shrinks in problem 7, the range is likely to shrink as well. Use a graph or table to see why this happens.