#Help with this algebraic proof

71 messages ยท Page 1 of 1 (latest)

unborn fractalBOT
wispy cradle
#

Can you explain how this works ?

#

You said that it is sufficient to show sqrt(a)+sqrt(b)=2

#

To establish the equality

#

(why not)

#

But then you used the conclusion ? And substituted in the hypothesis

jade fiber
#

Yes you are right it is not clear at all, I should have assumed โˆša+โˆšb=2 and then showed that both equation are same are just transformation of each other. Still I'm not sure if it is enough to conclude the proof. Sorry for the haphazard proof. I just quickly need to write it down for you all to see.

#

Hopeful someone will show us a rigorous proof for this.

jade fiber
#

Hi I finally proved it rigorously, I will forward the solution here.

wispy cradle
#

I have a solution

#

If you want

#

Hope my handwriting is clear

#

I first solve the system, then I show that sqrt(a)+sqrt(b) is equal to 2

jade fiber
#

Here is my solution:

#

@wispy cradle

wispy cradle
#

They are but I found x and y ๐Ÿ˜

jade fiber
#

Not required as per the question.

wispy cradle
#

Yeah so what

#

Our approaches are not exactly the same

#

You added the two equations and noticed that it is the expansion of (x+y)^3

#

I solved the system first
And then checked that the solutions satisfy x+y=2

jade fiber
#

Oh you are right

wispy cradle
#

But I could also find any other relationship between x and y such as x - 7y

jade fiber
#

But my proof is cleaner

#

That is required for rigorous proofs

wispy cradle
#

My proof is perfectly rigorous

jade fiber
#

No extra unnecessary stuff.

wispy cradle
#

You just did exactly the question

#

I did something more precise

#

How is that less clean

#

Your "proof" is strictly included in mine ๐Ÿ˜‚

jade fiber
#

But my proof is easier to read. Full stop.

#

Let's take opinion from the crowd instead of arguing

wispy cradle
#

Your proof is more basic yes

#

Mine requires a bit of reasoning

#

Both are valid

#

Why so salty

jade fiber
#

Extra reasoning were things can be solved using basic stuff is unnecessary.

wispy cradle
#

That's not really how real mathematics work

jade fiber
#

Lol I'm not xd

#

We should stop this xd

wispy cradle
#

Maybe for an exam yes

#

You just need to write a short answer

#

But here we are exploring a problem

jade fiber
#

Have you taken class on mathematical proofs?

wispy cradle
#

In case you didnt know

#

Im a maths teacher

jade fiber
#

Then you would understand why.

wispy cradle
#

๐Ÿ˜‚

jade fiber
#

OK then you do understand that being concise in proofs is must.

wispy cradle
#

This has nothing to do with being concise

jade fiber
#

Okay. Are you working on any cool problems? Or proofs?

wispy cradle
#

Being concise is great when you write a proof

#

And we both are very concise

#

In the above proof

#

Its just that I did something to go further

#

Doesnt mean its not a valid approach

#

Nor a bad proof

jade fiber
#

Ok

wispy cradle
#

I didnt include unnecessary arguments either

jade fiber
#

But you should remember that main reason for writing Proofs is to convince your reader with easy to read proofs without unnecessary symbols and it is important to keep your proofs short. Also for God's sake add a tombstone symbol at the end of your proofs (for the beauty obviously)

wispy cradle
#

If you focus on the ideas, you would realise my method is far superior than yours
Why ?
Because if any other question was asked about a and b your method would not hold

#

So yeah your method is "quick" but that doesnt mean its better

#

Perhaps whats even more problematic is not keeping an open mind

#

To other approaches

jade fiber
#

Your method might be superior than mine but it will be stretch to say that it is a good example of beautiful mathematical proof which in my case is.

#

Also if I need to find individual x and y, I can use Cardano's formula for the cubic equation for the closed form or Newton's method for the numerical result or some other method.

#

Also I guess we have criticised each other enough good night. ๐Ÿ‘

#

Nevertheless I would like to know what the audience will think about our methods.