Patterns and equations help please!

[lillybeth]

OK. I just started learning inputs and outputs and stuff like that today, and i'm really confused on these two questions. Please show me how to do the problems.

Which of the following sets of ordered pairs is not a function?

a). {(0, 2), (1, 4), (2, 5), (3, 6)}
b). {(-1, 2), (1, 3), (1, 5), (-3, 4)}
c). {(-4, 3), (-1, 1), (-2, 5), (3, 7)}


and


What are the inputs of the following function?
{(-3, 2), (-4, 2), (8, 3), 7, 1)}



Thanks for all the help guys!

 

[mmm4444bot]

Why have you stopped following our posting guidelines?

Do you need to refresh your memory?

 

[HallsofIvy]

OK. I just started learning inputs and outputs and stuff like that today, and i'm really confused on these two questions. Please show me how to do the problems.

Which of the following sets of ordered pairs is not a function?

Go back and review the definitions. What is the definition of "function"?

a). {(0, 2), (1, 4), (2, 5), (3, 6)}
b). {(-1, 2), (1, 3), (1, 5), (-3, 4)}
c). {(-4, 3), (-1, 1), (-2, 5), (3, 7)}


and


What are the inputs of the following function?
{(-3, 2), (-4, 2), (8, 3), 7, 1)}



Thanks for all the help guys!

 

[lillybeth]

Go back and review the definitions. What is the definition of "function"?

The definition of a function: (Yes, I followed your advice and looked it up) A function is a set of mathmatical operations performed on one or more inputs (variables) that the result is an output.

Do you want any more definitions? :| I still can't see how this is helping me get the answer, but I'll look up a few more terms.

 

[Deleted member 4993]

One property of function:

For each 'x' value there is only one 'y' value (translated from "exact math-speak")

so if the set is {(3,4), (3,7)} - then for x = 3 we have two y values [ 4 and 7]. Hence that set does not define a function.

This is sometimes called vertical-line test.

 

[lillybeth]

One property of function:

For each 'x' value there is only one 'y' value (translated from "exact math-speak")

so if the set is {(3,4), (3,7)} - then for x = 3 we have two y values [ 4 and 7]. Hence that set does not define a function.

This is sometimes called vertical-line test.

I'm all of the sudden really confused... I get that {(3,4), (3,7)} is a function. You know, the deeper this thread gets the more confused I get. Maybe I should just ask my teacher to go over this with me again?

 

[srmichael]

I'm all of the sudden really confused... I get that {(3,4), (3,7)} is a function. You know, the deeper this thread gets the more confused I get. Maybe I should just ask my teacher to go over this with me again?

Where do you get that (3,4) and (3,7) is a function???

 

[lillybeth]

Where do you get that (3,4) and (3,7) is a function???

My teacher taught me this thing called the vertical line test, and that is where you draw a graph, and lable out the points in a function or nonfunction. If the points meet going up or down in the same column, than it is not a function. That was how I got my answer. Please show me what I did wrong so I can correct it next time!

 

[srmichael]

My teacher taught me this thing called the vertical line test, and that is where you draw a graph, and lable out the points in a function or nonfunction. If the points meet going up or down in the same column, than it is not a function. That was how I got my answer. Please show me what I did wrong so I can correct it next time!

OK, I am throughly confused now. Yesterday I explained the vertical line test to you and you seemed to understand it. Now you are saying that (3,4) and (3,7) does NOT fail the vertical line test thus it's a function?? I beg to differ. As S Khan already mentioned these two points do NOT make a function. Plot them then connect them. It's a VERTICAL LINE, so the vertical line test FAILS!

 

[lillybeth]

ok.

OK, I am throughly confused now. Yesterday I explained the vertical line test to you and you seemed to understand it. Now you are saying that (3,4) and (3,7) does NOT fail the vertical line test thus it's a function?? I beg to differ. As S Khan already mentioned these two points do NOT make a function. Plot them then connect them. It's a VERTICAL LINE, so the vertical line test FAILS!

ok. I see now. But can we get back to my math problem instead of S Khan's? Nevermind. I already have the answer. No.

 

[JeffM]

The definition of a function: (Yes, I followed your advice and looked it up) A function is a set of mathmatical operations performed on one or more inputs (variables) that the result is an output.

Do you want any more definitions? :| I still can't see how this is helping me get the answer, but I'll look up a few more terms.

If the input is 3 and the result is sometimes 5 and sometimes 7, it is NOT a function. The output must be a perfectly defined one.

I think you are mixing up GRAPHING and a table.

\(\displaystyle x\ \ y\)
\(\displaystyle 1\ \ 8\)
\(\displaystyle 3\ \ 5\)
\(\displaystyle 3\ \ 7\)
\(\displaystyle 5\ \ 0\)

You can't use the vertical line test on a table. You use it on a GRAPH. If you do, you will find that the points (3, 5) and (3, 7) form a vertical line and so THIS IS NOT A FUNCTION.

You can determine from a table whether it is a function or not. If even one input does not have a distinct output, it is NOT a function. If any input appears more than once and does not have the same output EVERY TIME, it is NOT a function. Otherwise it IS a function.

 

[lillybeth]

reply to JeffM

If the input is 3 and the result is sometimes 5 and sometimes 7, it is NOT a function. The output must be a perfectly defined one.

I think you are mixing up GRAPHING and a table.

\(\displaystyle x\ \ y\)
\(\displaystyle 1\ \ 8\)
\(\displaystyle 3\ \ 5\)
\(\displaystyle 3\ \ 7\)
\(\displaystyle 5\ \ 0\)

You can't use the vertical line test on a table. You use it on a GRAPH. If you do, you will find that the points (3, 5) and (3, 7) form a vertical line and so THIS IS NOT A FUNCTION.

You can determine from a table whether it is a function or not. If even one input does not have a distinct output, it is NOT a function. If any input appears more than once and does not have the same output EVERY TIME, it is NOT a function. Otherwise it IS a function.

OK. Thankyou Jeff, I see it better now.

 

[Deleted member 4993]

OK. I just started learning inputs and outputs and stuff like that today, and i'm really confused on these two questions. Please show me how to do the problems.

Which of the following sets of ordered pairs is not a function?

a). {(0, 2), (1, 4), (2, 5), (3, 6)}
b). {(-1, 2), (1, 3), (1, 5), (-3, 4)}
c). {(-4, 3), (-1, 1), (-2, 5), (3, 7)}


and


What are the inputs of the following function?
{(-3, 2), (-4, 2), (8, 3), 7, 1)}



Thanks for all the help guys!

If you are saying that sets a), b) and c) - all describe functions - you are incorrect.

In each of those sets individually, do you see repeated input (x) ?

If you do - most probably it will fail vertical line test.

 

[lillybeth]

If you are saying that sets a), b) and c) - all describe functions - you are incorrect.

In each of those sets individually, do you see repeated input (x) ?

If you do - most probably it will fail vertical line test.

thats not what i ment!!! I know the answer because it was already graded:
question number 1: b is not a function
i will tell you what the next one was in a sec.

 

[lillybeth]

answer to question number 2: {-4, -3, 7, 8}

Thanks for the help guys, but i think this thread is closed.

 

[mmm4444bot]

answer to question number 2: {-4, -3, 7, 8}

That looks correct.

Your course should eventually teach you the name for this set of numbers. It's called the function's domain.

i think this thread is closed.

This thread is still open. You may determine whether a thread is closed by looking at the [Reply to Thread] button.

When a thread is closed, the name of that button changes to [Closed Thread].



Hint: If you limit your threads to discussing one exercise each, the discussions will be easier to follow. This is why the posting guidelines state: "PLEASE begin new threads for different exercises."

Cheers :cool:

 

[lillybeth]

reply to mmm4444bot

This thread is still open. You may determine whether a thread is closed by looking at the [Reply to Thread] button.

When a thread is closed, the name of that button changes to [Closed Thread].

What I meant by saying the thread was closed was that i didn't need any more help. But thanks anyway, I didn't know the name of the button changed when a thread was closed. Anyway, thanks for all the help guys, I really apreciate it!