Domain is the set of all x values and range is the set of all y values. Ordered pairs are written as (x, y). To find the domain, list all the x values from the set of ordered pairs. To find the range, list all the y values from the set of ordered pairs. Repeated values in the domain or range do not need to be written more than once.
There's lots of different situations in which you're going to be asked to find the domain and range. This is one type where you're given a set of points. Keep in mind the domain is the set of x numbers the range is the set of all y numbers.
So when you're given points like this, it's really not too hard. Let me show you what I mean the domain is going to be the set of my x numbers I'm going to write it using that little funky bracket to show that its a set. One, two, three, and four I got that from just looking at the x numbers.
The range is the set of all y numbers so again I'm going to use the funky bracket to show it's a set then you just look for the y values. 1/2, 1, 3/2 and 2 that's it when you're given problems and asked to find the domain and range again the hardest part is just keeping the vocabulary straight. If you can't, have your notes out next to you so you can look and say, "Wait is domain the x again or is that the range?" Keep that stuff handy in your notes so that you can remember which one's which.
Actually one thing I used to do when I was learning this stuff is I would put important vocabulary on a note card and then I would hang it in my shower, this is pretty dorky but you could do it, and so I would have domain and range in my shower. So every day for like ten minutes I was looking at the words and I remember, okay, okay domain is the Xs range is the Ys. You can try that if you want to it helps me to remember, domain is the set of Xs, range is the set of Ys.
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