point in math

Hi guys, I'm so confused about max of two points that they are the same, I mean if I have max(5,5) => 5
but I dont understand this, because max means the greatest point upon the points we have, but we have 5 ,5 so we don't have maximum point because none of two points (5,5) greater than each other, so the max() should return 0 and not 5 because the two points are not greater than each other , they are equal, so we have no greater one than the other one ... so the max should return 0 ..but sounds it's wrong as the video I watched for learning .. so anyone can help how can I define the max function?

thanks alot guys!!
 
You and your spouse go shopping for a bed. The salesman asks what size bed you need. You answer "Obviously, the maximum of our heights". He says "Ok, you are both 5' 8", here are our 0 size beds".
 
The max function on a set of numbers returns the lowest number that is NOT exceeded by any number in the set. It is a greater than or equal relationship.

The min function on a set of numbers returns the highest number that does NOT exceed any number in the set. It is less than or equal relationship.

As usual, your confusion arises because you do not pay careful attention to what things mean.
 
Ryan$ said:
Hi guys, I'm so confused about max of two points that they are the same,
I mean if I have max(5,5) => 5 but I dont understand this, because max means the greatest point upon the points we have
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You always like a formula. Well the max & min functions are well defined.
\(\displaystyle \large{\max\{a,b\}=\dfrac{|a+b|+|a-b|}{2}~\&~\min\{a,b\}=\dfrac{|a+b|-|a-b|}{2}}\)
Here are some to practice on:
\(\displaystyle \max\{1,-2\}=~?\)
\(\displaystyle \min\{1,-2\}=~?\)
\(\displaystyle \max\{5,5\}=~?\)
\(\displaystyle \min\{5,5\}=~?\)
\(\displaystyle \min\{-5,-5\}=~?\)
\(\displaystyle \max\{3,-3\}=~?\)
\(\displaystyle \min\{3,-3\}=~?\)
 
You already asked this question in February: https://www.freemathhelp.com/forum/threads/maximum.114387/

Please reread the answers there.

In English, the word "largest" can be taken to suggest there are more than one (in fact, maybe more than two) different values. But in math, we define it very simply, as the member of the set that is no less than any member of the set. This applies to any size set, and does not depend on the values being different.

In any language community (such as math), you just accept the definition that people use. This is part of being human. It is pathological to do otherwise.
 
Hi guys!
I already explained this but it's still not convincing me .. any help please? I really face that problem every time I solve mathmatics/physics !

why I can define Axis of x,y,z in whereever I want ? maybe someone else can define his own axis x,y,z so he will get his solution accordingly to his defining of axis, and not for example as what I defined in my solution .. so we have many solutions to one question .. sounds weird ! any help to close this gap?!
 
I have reported this as a violation of guidelines. No underlying problem has been given, and the exact same question was asked by the same poster before and then answered. Ryan should be banned.
 
You may orient a system of coordinate axes as you see fit to make a problem easier with which to work. If I define my own axes differently and work the same problem, and if we both make no mistakes, we will get the same solution.

Post the specific problem on which you worked using two different orientation of axes, and got differing solutions. Hopefully, we can spot the error(s) you made in one or both orientations.
 
JeffM said:
I have reported this as a violation of guidelines. No underlying problem has been given, and the exact same question was asked by the same poster before and then answered. Ryan should be banned.
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Yes, the OP should have used the existing thread in which to post, and should not be repeatedly ignoring our collective pleas to post actual problems instead of vague generalizations of scenarios.

@Ryan$ - Consider this a warning to amend your posting habits. We want to help you, but you must help us to help you. Please address my request above:

"Post the specific problem on which you worked using two different orientation of axes, and got differing solutions. Hopefully, we can spot the error(s) you made in one or both orientations."
 
MarkFL said:
You may orient a system of coordinate axes as you see fit to make a problem easier with which to work. If I define my own axes differently and work the same problem, and if we both make no mistakes, we will get the same solution.

Post the specific problem on which you worked using two different orientation of axes, and got differing solutions. Hopefully, we can spot the error(s) you made in one or both orientations.
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but once again you're talking with who don't have master in math, why I may orient a system of coordinate as I see?! maybe someone sees it different .. so ?! .. in math I can "define" whatever I want?!
 
Ryan$ said:
but once again you're talking with who don't have master in math, why I may orient a system of coordinate as I see?! maybe someone sees it different .. so ?! .. in math I can "define" whatever I want?!
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Do you understand my analogy with house numbers from the other thread?
 
This is not a seminar on philosophy!

Post a specific problem....
 
Ryan$ said:
but once again you're talking with who don't have master in math, why I may orient a system of coordinate as I see?! maybe someone sees it different .. so ?! .. in math I can "define" whatever I want?!
Click to expand...

Please post the problem on which you were working and which led to differing results based on differing orientations.
 
A coordinate system is something we impose upon a problem. For example, suppose we have a problem in which we are told that a rock is thrown upward, at 2 m/s, from a 200 m tall building. If I want to use y''= -g, I can set up a coordinate system in which y= 0 at the bottom of the building and have initial conditions y(0)= 500, y'(0)= 2. Or I could set up a coordinate system in which y= 0 at the top of the building and y= 200 at the bottom. Then we would have to use y''= g (since "+" is downward) with initial conditions y(0)= 0, y'(0)= -2.

Yes, solving those different problems gives different solutions for y (the first gives y(t)= -(g/2)t^2- 2t+ 500 and the second y(t)= -(g/2)t^2- 2t but interpreted in terms of the coordinate system, they give the same solution. In particular, if the question is "when does the rock hit the bottom, using the first "coordinate system" we need to solve the equation -(g/2)t^2- 2t+ 500= 0 and in the second, (g/2)t^2+ 2t= 500. Those two equations have exactly the same solution.
 
MarkFL said:
Please post the problem on which you were working and which led to differing results based on differing orientations.
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sir once again, if I have triangle and I defined my system coordination on left corner, and you defined it on the other corner .. so solution definitely would be different ! like for instance if you defined your positive axis like this ------------>
and I defined my z positive like this <--------------------------
so at the end solution would be corresponded to what we defined .. so solutions different
 
Ryan$ said:
sir once again, if I have triangle and I defined my system coordination on left corner, and you defined it on the other corner .. so solution definitely would be different ! like for instance if you defined your positive axis like this ------------>
and I defined my z positive like this <--------------------------
so at the end solution would be corresponded to what we defined .. so solutions different
Click to expand...

I mean please post the problem you were given, exactly as it was stated (translated to English of course), not simply the other vague scenario you previously posted.
 
Ryan$ said:
really not ! and sorry for saying that!
Click to expand...

We have 3 houses in a row on the same side of the street: A, B, C. Question: how many houses are there between A and C?
Let's say for the purposes of calculating the answer we number them 2, 4, 6. How many even numbers are there between 2 and 6? One - number 4. So, the answer is 1.
Now the let's switch where house numbers start to the other end of the street. The numbers of our houses now are 15, 13, 11. Same question. How many odd numbers are there between 15 and 11? One - 13. So, the answer is 1.
You can devise any numbering system (more the origin, etc), it will not affect the answer, since changing the system does NOT change the houses.
Same with coordinate systems in 2D or 3D. Moving the coordinate system around does NOT change the relationship between already existing objects.
 
You have a triangle and two different coordinate systems. You would get different solutions to what problem? You still haven't stated a problem!

But I think I understand what you are asking. If we are given a "word problem", we might let "x", "y", "z" represent the numerical values of things in the problem. It is always important that you state exactly what x, y, and z represent- you can't just start writing equations in x, y, and z without doing that (although many students do). And an answer cannot just be values for x, y, and z (although too many students do end with "x= ", "y= ", "z= ") you must state your solution to the problem in the same words as the word problem. The values of x, y, and z are not "the solution"- they lead you to it.
 
Well guys !
I can translate the problem, but the point of my post is to understand the concept of defining the coordination system.
***once again I may understand it wrong that's why I'm posting here ***
NOW THERE IS NO PROBLEM, I want to understand as you guys definitely know that we can use the coordinated system in any question I want to ..
what's confusing me, does it matter to the solution if I choose my own coordinated system and you choose your own coordinated system?
more precise, is the solution that we produce is respect to the coordination system that the solver choose?

thanks alot for your cooperation ! that's all what confusing me on coordination system ..
 
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