Melody

921 Questions
34315 Answers

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Mathigon website

I just discovered a site called mathigon

https://mathigon.org/dashboard
lee mas ..

Melody 2 abr 2022

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Reporting problems.

There are a number of people having problems at the moment.
If you lodge an error can you please give all relevant information that you can think of.
Where you are in the world - the city or the country - is often very important information. lee mas ..

Melody 16 mar 2022

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How to make an empty rectangle in Latex

I just worked out how to make an empty box of various horizonal size easily in LaTex.
This is not a recommended method, but other methods that I have tried here have not worked.
This coding is really simple. Just put letters inside lee mas ..

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Melody 15 mar 2022

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HAPPY ANNIVERSARY CHRIS! (CPhill)

I just realized that you became a member here exactly 8 years ago today!

It has been great to have you here all that time

Fuera tema

Melody 13 mar 2022

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WELCOME BACK CPHILL !

Melody 11 feb 2022

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Very interesting question. No high level maths required.

This question was posted a couple of days ago.
https://web2.0calc.com/questions/geometry_73561

I think it is really interesting. It looks much more difficult than it really needs to be. lee mas ..

Melody 1 feb 2022

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Members have a better experience. Their questions get more attention.

Almost everyone is posting as a guest.
If you post as a member your questions will have a far greater chance of a timely and helpful response.
If you are a genuine learner and interact with us, you will become known and answerers will do lee mas ..

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Melody 9 ene 2022

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HAPPY BIRTHDAY CHRIS!

Melody 20 dic 2021

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Some guidelines for question askers.

Please note:
1) Ask only one question per post.
2) When asking a question talk about what you have tried for yourself. Then people will take you more seriously and will be more able and willing to help.
3) If you get an answer lee mas ..

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Melody 4 nov 2021

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Remeniscing - a little historical humour.

I just found this old post that some of you, who have been around for a while, might find amusing.

https://web2.0calc.com/questions/look-at-the-new-leader-board

Fuera tema

Melody 29 oct 2021

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Do the 9s keep going for ever or do you know how many 9s there are ?

Melody11 dic 2013

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coolGuy:
how much is 1 to the power of 6

Well, it is 1*1*1*1*1*1 (A * is a times sign)

So coolGuy, why don't you tell us the answer?

Melody11 dic 2013

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Nox:
x=-4y^2-4y+1 Graph the following horizontal parabola. How would one get this answer. Please show work.

It is just about the same as a vertical parabola.

Use the quadratic formula to get the roots. These will go on the y axis because you are solving for x=0 (and the equation of the y axis IS x=0)
I got y= -1/2 + root2/2 and y= -1/2 - root2/2 So you can plot thes points

now the axis of symetry is y= -1/2 ( you should be able to see that from the value of the roots)

Substitute y= -1/2 inot the initial equation to get the x value of the turning point. I got x=2

So the turning point is (2, -0.5)

3 points is all you need to define a parabola so now you have finished.
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Now there are some interesting facts that it would be good for you to think about.

y = -4x ² - 4x + 1 and x = -4y ² + 4y +1 are called inverse functions. That is, they are each the inverse of the other one.

This is true for ANY equations where the x and the y swap places.

All inverse functions are reflections of each other about the line y=x.

Why don't you sketch the other functions and convince yourself that this is correct.

Or you could look at 2 really easy ones like y=2x and x=2y

anyway this can sometimes be a very handy thing to know when you are sketching, or dealing with functions.

Melody11 dic 2013

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The Quadratic Formula is a mathematical expression used to solve quadratic equations such as (ax (squared) +bx+c=0. The origin of the quadratic formula begin in about 2000 BC among the Egyptians and Chinese.

At the end of the 16th Century the mathematical notation and symbolism was introduced by amateur-mathematician François Viète, in France. In 1637, when René Descartes published La Géométrie, modern Mathematics was born, and the quadratic formula has adopted the form we know today.

It seems there is a long history to it
for more info see
http://h2g2.com/approved_entry/A2982567

Melody11 dic 2013

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What rectangle?

Melody11 dic 2013

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I know! I know! At least I'm pretty sure that i do.

Hi Reasonforeverything,
I've been watching your posts. It is great that you have joined the forum!
Melody.

Melody11 dic 2013

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this is a good answer reasonforeverything.

the only thing I would like to point out is that sometimes children learn percantages before they know anything at all about algebra.

Melody11 dic 2013

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Hi Annabelle,
Did Professor Lopez just do your homework for you?
You know that is not the way you should be using this forum.
We are here to help you learn but not to do a whole page of homework.

Anyway, some of the Professors answers are a little dodgy, so you'd better do some of your own thinking.
I don't remember seeing you on the forum before Annabelle, but you are very welcome, we enjoy having lots of different nationalities and languages here.

Hi Professor, I hope you don't mind me saying these things. I love it that we are both on this forum.

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Salut Annabelle,
Professeur Lopez fait juste vos devoirs pour vous ?
Vous savez c'est pas la façon dont vous devriez utiliser ce forum.
Nous sommes là pour vous aider à apprendre, mais ne pas faire une page entière du travail à domicile.

De toute façon, certaines réponses professeurs sont un peu douteux, alors vous feriez mieux certains de votre propre réflexion.
Je ne me souviens pas vous voir sur le forum avant d'Annabelle, mais tu es la bienvenue ici, nous avons plaisir à avoir beaucoup de différentes nationalités et langues ici.

Salut professeur, j'espère que vous ne voudrez pas me dire ces choses. Je l'aime que nous sommes tous les deux sur ce forum.

Melody11 dic 2013

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Ridgway:
Mitosis is a process of cell reproduction in which one cell divides into two identical cells. E. coli is a fast-growing bacterium that is often responsible for food poisoning in uncooked meat. It can reproduce itself in 15 minutes. If you begin with 100 E. coli bacteria, how many will there be in 1 hour?

In the beginnig there are 100
After 15mi there are 2*100=200
After 30 minutes there will be 2*200 =

I think that you can finish this.

Melody11 dic 2013

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ddd:
If x = y then does y=x ?
I just get confused with all the letters and numbers put in one problem. They all get mixed up in my head..

Whenever I have a problem that is a bit confusing I swap the numbers or letters for easier things and then I can often see better what I am allowed to do.

x and y are letters, that is why it is confusing
so I am going to swap them for something else

1+4 = 8-3 that's true isn't it?
so lets look at
8-3 = 1+4 is that still true?

or
1/2 = 0.5
does 0.5=1/2?

or
2*8=16
does 16=2*8?

so
If x=y
does y=x?

Melody11 dic 2013