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#1 2016-12-24 04:01:41

Hannibal lecter
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Registered: 2016-02-11
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How to right imaginary number with inequalities and in..

Hi,
How to right imaginary number with inequalities and in interval notation like this :

x^2 ≥ -1

it is either x ≥ + √-1

or x ≥ - √-1


so how to right it in number Line? and in interval notation,


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

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#2 2016-12-24 04:43:23

zetafunc
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Re: How to right imaginary number with inequalities and in..

The complex numbers don't form an ordered field. Think about it: what does it mean to say that
? The only way we can compare 'sizes' of complex numbers is to take the modulus. The most you can say is that
.

If
is a real number, then
, always. In fact, that's sometimes given as the definition of a real number.

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#3 2016-12-24 05:48:13

Hannibal lecter
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Registered: 2016-02-11
Posts: 146
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Re: How to right imaginary number with inequalities and in..

but I got this while I was trying to solve an inequality : 


it make me feel confused with this x^2 + 1

I don't know how to end my solution

Last edited by Hannibal lecter (2016-12-24 05:52:23)


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#4 2016-12-24 07:52:05

zetafunc
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Re: How to right imaginary number with inequalities and in..

You can just multiply both sides by
(since it is always positive) to get
Do you see where to go from here?

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#5 2016-12-24 09:30:58

Hannibal lecter
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Registered: 2016-02-11
Posts: 146
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Re: How to right imaginary number with inequalities and in..

yes, the interval will be (-∞,-1] U [1,∞) right?

Last edited by Hannibal lecter (2016-12-24 09:31:21)


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#6 2016-12-24 09:52:12

zetafunc
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Re: How to right imaginary number with inequalities and in..

Yes.

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#7 2016-12-24 09:53:19

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

Re: How to right imaginary number with inequalities and in..

Hi;

That is what I am getting.


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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#8 2016-12-24 10:10:35

Hannibal lecter
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Registered: 2016-02-11
Posts: 146
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Re: How to right imaginary number with inequalities and in..

now I'm good with absolute value hehehe but I'm not genius, I need to be genius in the future


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

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#9 2016-12-24 10:15:50

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

Re: How to right imaginary number with inequalities and in..

I knew a kid who everyone told him he was a genius. Pretty soon, his head got so big he could not squeeze it through his own front door. A few nights outside in the cold brought him back to reality and his head shrunk to normal size. He became a hard worker and forgot that genius stuff. He does not do much better than when he believed he was a god but he at least can get home and go through the door. The moral of this story? I have no idea.


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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#10 2016-12-24 10:23:56

Hannibal lecter
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Registered: 2016-02-11
Posts: 146
Website

Re: How to right imaginary number with inequalities and in..

thank you


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