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#651 2014-10-04 06:37:49

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

Re: Simplify the following:

Wait, yours is getting the right answer too. My apology.


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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#652 2014-10-04 06:54:04

EbenezerSon
Member
Registered: 2013-07-04
Posts: 554

Re: Simplify the following:

I am very sure if I see your steps would help me know how to go about a similar problem.


I know only one thing - that is that I know nothing

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#653 2014-10-04 06:57:57

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

Re: Simplify the following:

Divide both sides by - 3

and the rest is easy.


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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#654 2014-10-04 07:01:08

EbenezerSon
Member
Registered: 2013-07-04
Posts: 554

Re: Simplify the following:

Hi;
please - show the steps of my idea too.


I know only one thing - that is that I know nothing

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#655 2014-10-04 07:10:18

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

Re: Simplify the following:

I am sorry but that I can not do since I do not understand it.


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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#656 2014-10-14 09:22:55

EbenezerSon
Member
Registered: 2013-07-04
Posts: 554

Re: Simplify the following:

bobbym wrote:

Divide both sides by - 3

and the rest is easy.


Please - continue I am not getting the answer


I know only one thing - that is that I know nothing

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#657 2014-10-14 09:26:05

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

Re: Simplify the following:

Raise both sides to the 8^  that will make the

disappear.

x = 8^(-2/3)


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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#658 2014-10-16 19:07:15

EbenezerSon
Member
Registered: 2013-07-04
Posts: 554

Re: Simplify the following:

In fact, I am well familiar with my method - but unfortunately I can't arrive on 1/4 as the answer


I know only one thing - that is that I know nothing

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#659 2014-10-16 20:50:15

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

Re: Simplify the following:

If it can not get the correct answer then either you are not using it right or the the method is not that good.


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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#660 2014-10-17 08:12:51

EbenezerSon
Member
Registered: 2013-07-04
Posts: 554

Re: Simplify the following:

log(x+1) - 2logx^2 = 1
log(x+1/x^2) = log10
Anti-log taking at both sides
x + 1 = 10x^2
9x^2 = 1
x^2 = 1/9
x = +1/3
This method is quite understandable to me, but to my suprise I can not use it to solve the one under discussion literally for many days


I know only one thing - that is that I know nothing

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#661 2014-10-17 08:55:42

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

Re: Simplify the following:

Why do you think those logs are to the base 10?

If they are it is going to lead to a cubic in which 1 / 3 is not an answer.


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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#662 2014-10-19 18:06:08

EbenezerSon
Member
Registered: 2013-07-04
Posts: 554

Re: Simplify the following:

The book tells that, if the base is not written then it in base 10. What do say? Again, are you saying it is a wrong answer?

[the book solved it]

Last edited by EbenezerSon (2014-10-19 18:08:12)


I know only one thing - that is that I know nothing

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#663 2014-10-19 22:13:26

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

Re: Simplify the following:

Are we talking about log(x+1) - 2logx^2 = 1?


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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#664 2014-10-20 00:08:09

EbenezerSon
Member
Registered: 2013-07-04
Posts: 554

Re: Simplify the following:

bobbym wrote:

Are we talking about log(x+1) - 2logx^2 = 1?


Yes.


I know only one thing - that is that I know nothing

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#665 2014-10-20 00:12:37

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

Re: Simplify the following:

If x = 1 / 3 is a solution when you plug in the equation should now be true.


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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#666 2014-10-20 00:18:18

EbenezerSon
Member
Registered: 2013-07-04
Posts: 554

Re: Simplify the following:

It seems I am not getting you


I know only one thing - that is that I know nothing

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#667 2014-10-20 00:24:27

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

Re: Simplify the following:

Okay, let us do something simpler and then we will come back to this.

When we say we solved an equation it means we have found the x value that makes the equation true.

Supposing we have this equation:

x + 5 = 10

if we now said that x = 6 is a solution when we plug in for x we get

6 + 5 does not equal 10 so we have not solved the equation. x = 6 is not a solution.

If we say x = 5 is a solution when we plug in we find

5 + 5 = 10 this is true! So, x = 5 is a solution to the equation x + 5 = 10.

Do you follow?


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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#668 2014-10-20 00:27:23

EbenezerSon
Member
Registered: 2013-07-04
Posts: 554

Re: Simplify the following:

Yes I  see now


I know only one thing - that is that I know nothing

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#669 2014-10-20 00:35:05

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

Re: Simplify the following:

Now, the same thing holds for more complicated equations. If x = 1 / 3 was a solution to log(x+1) - 2logx^2 = 1 then when we plug in or replace x by 1 / 3 in it the statement should be true. It does not matter what method we use to ge this value of x, the plug in rule must always apply.

Now when you plug in x = 1 / 3 into log(x+1) - 2logx^2 = 1 is that true?


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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#670 2014-10-20 04:55:26

EbenezerSon
Member
Registered: 2013-07-04
Posts: 554

Re: Simplify the following:

Hi, Bobbym, I was called away, I am sorry - but I don't have my calculator with me now.
It is negative or positive 1/3 in the book as an answer. When I get to  the house I will punch them in the calculator and see if it really gives negative or positive 1/3.

Last edited by EbenezerSon (2014-10-20 04:56:30)


I know only one thing - that is that I know nothing

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#671 2014-10-20 05:01:19

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

Re: Simplify the following:

See if  log(x+1) - 2logx^2  equals 1.


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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#672 2014-10-21 03:42:25

EbenezerSon
Member
Registered: 2013-07-04
Posts: 554

Re: Simplify the following:

No, it doesn't give 1/3


I know only one thing - that is that I know nothing

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#673 2014-10-21 03:49:09

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

Re: Simplify the following:

So we know that x = 1 /3 or x = - 1 / 3 is not a solution.

When I solve for that I get a very complicated expression. This is not likely for a textbook.

Did you copy the problem correctly?


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.

Offline

#674 2014-10-21 03:58:49

EbenezerSon
Member
Registered: 2013-07-04
Posts: 554

Re: Simplify the following:

Yes that's the problem - I copied it correctly.

When you plug in your answers does it give 1?


I know only one thing - that is that I know nothing

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#675 2014-10-21 04:04:26

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

Re: Simplify the following:

Yes, it does.


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.

Offline

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