Domain and Range..? Help me Please!
- Thread starter tinyniel
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A function is a pairing of inputs and outputs, with only one output defined for any input. The domain is the set of inputs. The range is the set of outputs. Using common parlance, the x-values are the domain, and the y-values are the range.
For further information, since we can't really teach lessons in this context, try a search engine for lessons on functions, function notation, and domain and range.
Eliz.
For further information, since we can't really teach lessons in this context, try a search engine for lessons on functions, function notation, and domain and range.
Eliz.
There are an infinite number of functions that hit three points but the simplest is a parabola. Unless you are hiding a clue I would assume that it is an upward opening parabola with the vertex at (0,-1) going thru the other two points.
You should be able to find the domain and range info in Staples suggested sites.
You should be able to find the domain and range info in Staples suggested sites.
- Joined
- Feb 4, 2004
- Messages
- 16,583
Gene: I don't think the poster has to find the equation of a line that passes through the given points. Those points are the function, and the poster is supposed to give the domain and the range of the function. (This is a fairly common exercise any more.)
Of course, the poster then agreed with you that the function is in fact a parabola, which wasn't included in the original post, so I could be mistaken.
tinyniel: What you'd posted originally was one sort of exercise, but your reply to Gene makes it seem that this is instead a very different sort of exercise. Please reply with the full text of the exercise, including a detailed description of any associated graphic (such as the parabola whose vertex you have verified to Gene).
Thank you.
Eliz.
Of course, the poster then agreed with you that the function is in fact a parabola, which wasn't included in the original post, so I could be mistaken.
tinyniel: What you'd posted originally was one sort of exercise, but your reply to Gene makes it seem that this is instead a very different sort of exercise. Please reply with the full text of the exercise, including a detailed description of any associated graphic (such as the parabola whose vertex you have verified to Gene).
Thank you.
Eliz.
I didn't intend to suggest that the function sould be worked out though it could be. Just knowing the vertex lets you determine the domain and range, given that it is a parabola. Domain is -inf to +inf, range is vertex to (+ or -) inf for ANY vertical parabola. I jumped to my (unwarented) conclusion 'cause the domain and range of three lonely points seems nonsense to me, though it is mathmaticaly correct. I'm not up on the "fairly common exercises."
I edited out the circle reference when Eliz reminded me of the single value part of a function. You can draw a circle thru any three points so that is one of the infinite number of curves that contain those points but most xs have 2 ys so it isn't a function. The botom half could be.
f(x)=-sqrt(r²-x²) would qualify.
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Gene
I edited out the circle reference when Eliz reminded me of the single value part of a function. You can draw a circle thru any three points so that is one of the infinite number of curves that contain those points but most xs have 2 ys so it isn't a function. The botom half could be.
f(x)=-sqrt(r²-x²) would qualify.
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Gene