Please tell me how to prove the set is a relation, function or both or none!?

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dollyayesha2345

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In Exercises 21-24, consider the set of all ordered pairs (x,y) as described. Is the set a relation? Is it a function?
21. (x,y), where x is the name of a telephone subscriber in your town and y is the subscriber's telephone number.
22. (x,y), where x is the name of each mother in your town and y is the name of her child.
23. (x,y), where x is each man in London, England and y is his right thumb pint.
24. (x,y), where x is any nonvertical line in the coordinate plane and y is its slope.

MY ANSWERS:
21. Yes, it is a relation and function
22. Yes, it is a relation
23. No neither relation nor function
24. Both relation and function

Note: Please do not judge me. I don't have notes, textbook anything at my end all I have is these 4 questions. I have shared what I think is the correct answer. If I'm wrong please correct me and do let me know how to prove my answer.
 
dollyayesha2345 said:
In Exercises 21-24, consider the set of all ordered pairs (x,y) as described. Is the set a relation? Is it a function?
21. (x,y), where x is the name of a telephone subscriber in your town and y is the subscriber's telephone number.
22. (x,y), where x is the name of each mother in your town and y is the name of her child.
23. (x,y), where x is each man in London, England and y is his right thumb pint.
24. (x,y), where x is any nonvertical line in the coordinate plane and y is its slope.

MY ANSWERS:
21. Yes, it is a relation and function
22. Yes, it is a relation
23. No neither relation nor function
24. Both relation and function

Note: Please do not judge me. I don't have notes, textbook anything at my end all I have is these 4 questions. I have shared what I think is the correct answer. If I'm wrong please correct me and do let me know how to prove my answer.
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You found this forum - you have internet. Find the definitions of the concepts involved and see whether the relationships fit the definitions. That's how you prove it.
 
In # 23 does "right thumb pint" actually mean "right thumb print"?
 
dollyayesha2345 said:
In Exercises 21-24, consider the set of all ordered pairs (x,y) as described. Is the set a relation? Is it a function?
21. (x,y), where x is the name of a telephone subscriber in your town and y is the subscriber's telephone number.
22. (x,y), where x is the name of each mother in your town and y is the name of her child.
23. (x,y), where x is each man in London, England and y is his right thumb p[r]int.
24. (x,y), where x is any nonvertical line in the coordinate plane and y is its slope.

MY ANSWERS:
21. Yes, it is a relation and function
22. Yes, it is a relation
23. No neither relation nor function
24. Both relation and function

Note: Please do not judge me. I don't have notes, textbook anything at my end all I have is these 4 questions. I have shared what I think is the correct answer. If I'm wrong please correct me and do let me know how to prove my answer.
Click to expand...
It will be helpful if you tell us the reasons for your answers (because that is your "proof"). Some depend on assumptions about non-mathematical facts, such as whether someone can have more than one phone (and if only one is considered "his telephone number"). I'm particularly interested in your thoughts on #23.

I'm also a little troubled that you would be given this assignment without an official reference, because when you search for definitions online, they will sometimes vary. I'd like to see the definitions you are using. (This is not a judgment of you, but possibly of your school.)
 
dollyayesha2345 said:
the question just says "pint" might be "print" but no clue
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To dollyayesha2345: Why do you refuse to answer the question posed to in reply #4?
The problem with our giving you help is simply that we do not know the definitions with which you are working.
It may surprise you but there are no standard definitions for relations & functions.
That simple fact is the reason that the answers to reply #4 are so important.
 
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