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#51 2017-01-29 21:17:51

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

Re: HI please solve this absolute value equation with interval notation ..

He told you did a crime in mathematics science when you wrote it like that!!!

Did he say I committed a mathematical crime? Hmmm, back in my younger days I would take offense at such an impertinent remark, but nowadays, I do not care. I do not even understand why he is so bothered by this question but it is typical. What is important is that we all got the same answer finally.

In this position, do I have to take the limit R.H.S or the f(0)?

As I understand them those two things are not interchangeable.


In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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#52 2017-01-30 08:12:15

Hannibal lecter
Member
Registered: 2016-02-11
Posts: 144
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Re: HI please solve this absolute value equation with interval notation ..

bobbym wrote:

In this position, do I have to take the limit R.H.S or the f(0)?

As I understand them those two things are not interchangeable.


do you mean when I have x in the second H.S I can't tell (limit L.H.S = limit R.H.S)
I have to say ( f(0) = R.H.S)

cause when we will have x inside this so : (xk^2+k-3)

and when we will take the limit L.H.S = Limit R.HS s0 ..
limit x+1 = limit xk^2+k-3       ((x apro to 0)
1= 0 + k- 3
k=1+3 = 4

is that right? or it will be wrong...

just tell me this please..


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#53 2017-01-30 08:40:45

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

Re: HI please solve this absolute value equation with interval notation ..

do you mean when I have x in the second H.S I can't tell (limit L.H.S = limit R.H.S)
I have to say ( f(0) = R.H.S)

I did not say that. There are so many things wrong with his question it is difficult to explain away each one.

First, let me say in light of what I was told, my answer, your answer and his answer are all incorrect.


In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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#54 2017-01-30 08:46:29

Hannibal lecter
Member
Registered: 2016-02-11
Posts: 144
Website

Re: HI please solve this absolute value equation with interval notation ..

bobbym wrote:

do you mean when I have x in the second H.S I can't tell (limit L.H.S = limit R.H.S)
I have to say ( f(0) = R.H.S)

I did not say that. There are so many things wrong with his question it is difficult to explain away each one.

First, let me say in light of what I was told, my answer, your answer and his answer are all incorrect.


no no sorry I didn't mean by that.. I just asked a question ( do you mean ...)

sorry it is my bad language and I didn't understand you so well because my bad translation sorry again...
it was just a question,...

so what is the correct answer..
and what is the wrong in his question

if the question was wrong how do I'll get the 10 marks hehe!!
what to do please help me in everything you can
and what is the k value???

Last edited by Hannibal lecter (2017-01-30 08:48:00)


Wisdom is a tree which grows in the heart and fruits on the tongue

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#55 2017-01-30 09:19:03

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

Re: HI please solve this absolute value equation with interval notation ..

This was the question you gave:

I said this equals 1.

First he said it equals 0 and then he said it equals 1.

The point they are telling me is that since x does not equal 0 it is pointless to say what happens as x approaches 0. The limit does not exist and therefore RHS is undefined, so there is no way to answer the question of what k is in k^2 + 3k -3.


In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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#56 2017-01-30 09:53:36

Hannibal lecter
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Registered: 2016-02-11
Posts: 144
Website

Re: HI please solve this absolute value equation with interval notation ..

if the Limit does not exist can we say just k^2+3k-3 = 0  (just make it equal to zero then find the solution it if can be)

or we can't?...................(1)

so now I understand.... the limit does not exist because x approaches to 0

.I'm afraid maybe he will change his answer again and tell me like what did you told me and he will say you must write in your paper (there is no way to find k ...............(2)  ) sad(

thank you very much


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#57 2017-01-30 12:01:21

Hannibal lecter
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Registered: 2016-02-11
Posts: 144
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Re: HI please solve this absolute value equation with interval notation ..

but I saw a lot of textbook that,  they toke the Limit or the R.H.S cause x ≠0 she these example please :

http://archives.math.utk.edu/visual.calculus/1/continuous.5/

https://www.math.ucdavis.edu/~kouba/CalcOneDIRECTORY/continuitydirectory/Continuity.html


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#58 2017-01-30 12:14:00

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

Re: HI please solve this absolute value equation with interval notation ..

if the Limit does not exist can we say just k^2+3k-3 = 0

No we can not. If the limit of the LHS does not exist we can not say that the LHS = 0.

I am going to go with my original conclusion. The limit of the LHS is 1. Now we are all in agreement again.


In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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#59 2017-01-30 21:17:53

Hannibal lecter
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Registered: 2016-02-11
Posts: 144
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Re: HI please solve this absolute value equation with interval notation ..

How is that be?


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#60 2017-01-31 06:01:24

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

Re: HI please solve this absolute value equation with interval notation ..

Hmmm, what do you think it is?


In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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#61 2017-01-31 10:16:19

Hannibal lecter
Member
Registered: 2016-02-11
Posts: 144
Website

Re: HI please solve this absolute value equation with interval notation ..

I don't have any Idea please help me the course will end in the end of the week so I will not be able to change my marks......

please!!!


Wisdom is a tree which grows in the heart and fruits on the tongue

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#62 2017-01-31 10:40:28

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

Re: HI please solve this absolute value equation with interval notation ..

The only thing I can say is I think it is 1, now your teacher thinks it is 1, some people think it is non-existent. So I asked what do you think it is.

What help can I give you?


In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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#63 2017-02-01 09:39:19

Hannibal lecter
Member
Registered: 2016-02-11
Posts: 144
Website

Re: HI please solve this absolute value equation with interval notation ..

I need scientific reasons to proof my solution that is right and not wrong,

because the the Associate Dean for Academic Affairs((he is an professor in mathematics)) and the Dean of the university
say to me that your answer was wrong????????????

please help me they all against me, they say the end of the result is right but when I said ( Limit R.H.S = limit L.H.S) that wrong and you must write it (LIMIT L.H.S = f(0) )  .

please Help me!  Put yourself in my place, what would you do with them?

please ! I'm weak and they are Dr and  Professor and lecturer all against me or against one that maybe wrote a simple mistake

Last edited by Hannibal lecter (2017-02-01 09:39:39)


Wisdom is a tree which grows in the heart and fruits on the tongue

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#64 2017-02-01 11:36:40

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

Re: HI please solve this absolute value equation with interval notation ..

I'm weak and they are Dr and  Professor and lecturer all against me or against one that maybe wrote a simple mistake.

Can you please post the original problem exactly as it was given to you?


In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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#65 2017-02-01 21:57:20

Hannibal lecter
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Registered: 2016-02-11
Posts: 144
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Re: HI please solve this absolute value equation with interval notation ..

this is the problem in Q2 see it please :

148602938360891.jpg


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#66 2017-02-01 22:06:09

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

Re: HI please solve this absolute value equation with interval notation ..

That is a totally different problem then you have had me working on!


In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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#67 2017-02-02 04:54:33

thickhead
Member
Registered: 2016-04-16
Posts: 1,086

Re: HI please solve this absolute value equation with interval notation ..

Bobbym,
That is what he stated before and I had understood it the same way.


{1}Vasudhaiva Kutumakam.{The whole Universe is a family.}
(2)Yatra naaryasthu poojyanthe Ramanthe tatra Devataha
{Gods rejoice at those places where ladies are respected.}

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#68 2017-02-02 05:46:02

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

Re: HI please solve this absolute value equation with interval notation ..

I have to disagree, Q2 in post #65 looks like a piecewise function. It is also the first time I am seeing it. There is no mention of limits at all. I probably would not have got that far anyway.


In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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#69 2017-02-02 08:05:38

Hannibal lecter
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Registered: 2016-02-11
Posts: 144
Website

Re: HI please solve this absolute value equation with interval notation ..

so, what is your explanation for this now please?
tell me please everything in one post. I have to finish what began.


Wisdom is a tree which grows in the heart and fruits on the tongue

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#70 2017-02-02 10:01:43

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

Re: HI please solve this absolute value equation with interval notation ..

Now that I know we are looking to make a piecewise function continuous at x = 0.

This page says http://www.themathpage.com/aCalc/contin … nction.htm

We say that a function f(x) that is defined at x = c is continuous at x = c

if the limit of f(x) as x approaches c

is equal to the value of f(c)

Using the definition of the piecewise function:

Again using the definition of the piecewise function.

We set both these equal to each other:

{k = -4}, {k = 1}

So based on this way both you and your teacher have the wrong answer in post #42.

148570442789571.jpg

He can choose to call my work criminally insane all he wants. He did it his way and got the wrong answer. I did it my way and got the right answer...Unfortunately, you can not argue with him because you have the wrong answer too.


In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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#71 2017-02-02 10:48:26

Hannibal lecter
Member
Registered: 2016-02-11
Posts: 144
Website

Re: HI please solve this absolute value equation with interval notation ..

I wrote it in the exam {k = -4}, {k = 1} like you did, and my teacher did,
but I copy it wrong here for you believe me! ....
these number not important,

the important is... the first step cause he want the first step to be right...

so, 

and not the lim L.H.S = lim R.H.S ( like I said)

so the teacher is right in the first step right?

sad

he don't want the  final answer.. he want the first step, he is make excuses to give me 0 ....
so now I can't say   

???

Last edited by Hannibal lecter (2017-02-02 10:50:33)


Wisdom is a tree which grows in the heart and fruits on the tongue

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#72 2017-02-02 11:48:33

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

Re: HI please solve this absolute value equation with interval notation ..

His first step is correct.

so now I can't say

There is no reason to take two limits.

We say that a function f(x) that is defined at x = c is continuous at x = c

    if the limit of f(x) as x approaches c

    is equal to the value of f(c)

Your teacher and I did it the same way on that step also.

And of course, the worst error in thinking that you made in the entire thread.

Hannibal wrote:

these number not important,

The purpose of math is to arrive at the correct numbers! This is what happens when the numbers are wrong.

https://www.youtube.com/watch?v=j4JOjcDFtBE


In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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