Melody

921 Questions
34315 Answers

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Mathigon website

I just discovered a site called mathigon

https://mathigon.org/dashboard
read more ..

Melody Apr 2, 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. read more ..

Melody Mar 16, 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 read more ..

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Melody Mar 15, 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

off-topic

Melody Mar 13, 2022

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WELCOME BACK CPHILL !

Melody Feb 11, 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. read more ..

Melody Feb 1, 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 read more ..

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Melody Jan 9, 2022

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HAPPY BIRTHDAY CHRIS!

Melody Dec 20, 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 read more ..

off-topic

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Melody Nov 4, 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

off-topic

Melody Oct 29, 2021

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mymathquestions:
If I have an angle whose measure is 10 degrees more than twice it's complement, what is the measure of that angle?

For starters, complementary angles add up to 90 degrees.
It is supplementary angles that add to 180 degrees.
This may help you remember. 2*90=180 and 2 Cs make an S. I am talking visually. An S has a C at the top and a back-to-front C on the bottom

I see Bertie has just answered so I don't need to say more. Thanks Bertie.

MelodyApr 1, 2014

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Okay, thanks Alan. It still looks like a friendly alternative but I guess there is not a need for multiple number presentations.

MelodyMar 31, 2014

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Hi all,
Another quiet Sunday/Monday.
Great answers from CPhill, mathcalc, Alan and Kitty3. Thank you.
Also thanks were received from ohnonotmaths and purple. It is always nice when people show their appreciation.

NEW MEMBERS
I just made a new information post for new members - it is tacked onto the 'become a member' thread. Please read it.
http://web2.0calc.com/questions/viewtopic.php?f=2&t=8806&p=22395#p22395

I hope your new week is off to a good start.
Melody.

MelodyMar 31, 2014

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NEW MEMBER INFORMATION

Welcome to web2.0calc. forum.
We hope that you find our forum very useful and that you like it here. (It is your forum too now)

Some hints on how to get the most out of the forum:
When you ask a question make sure it really makes sense and cannot be misinterpreted.
Make good use of the preview button.
Also try to be interactive with the person/people who are trying to help you. You will learn better that way and we will learn to improve our teaching techniques.
If you don't understand tell us.
If you are happy then say thank you.
Take a little time to read our information posts, you may learn some things that save you a lot of time in the longer term.
There is also a search function that works quite well.

If you want to answer questions you are very encouraged to do so. If you are not sure of the answer then say so but you can answer anyway.
Please do not give answers only. You have to explain how you get to the answer otherwise the asker will not learn anything.
You do not need to answer in full, you can just give a hint if you want to.
OR you can add your question to the original question if you want even more explained.

The forum belongs to all of us. Treat it and the people in it with respect and enjoy yourself.

PRIVATE MESSAGES
There is a private message centre here. You can find it by left clicking on your username. Then just click into the message centre.
If you go into the user control panel then Board Preferences (at the top of the message page), you can get a pop-up display for new messages, that is if you wish to do so.
If you send a message it will sit in your outbox until the recipient opens it. In the mean time you can edit it or delete it if you wish. It only moves to sent mail after the recipient opens it. If you delete the message the recipient will still get a message but it will just say 'message deleted before delivery' It is a really cool system. I wish my usual email worked this way.

Melody.

MelodyMar 31, 2014

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Thank you Alan,
I had not heard of engineering notation before but it does make good sense to present numbers in this way.
Hopefully I will remember it.
Melody.

MelodyMar 31, 2014

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mathgeek12:
the problem is: 15x2(2 is an exponent) - 6x - 9 = 0. WHat negative value of x is a solution to the quadratic equation?

15x ² - 6x - 9 = 0

Divide through by 3 just the same as CPhill did.

5x ² - 2x - 3 = 0

Now, how do you go about finding the factors?

5*-3 = -15
You have to look for two numbers that multiply to -15 and add to -2
Since they multiply to a negative number, one will be neg and the other positive. Since they add to a negative, there 'bigger' one will be negative
Must be -5 and +3
-2x becomes -5x+3x

5x ² - 2x - 3 = 0 becomes
5x ² - 5x+3x - 3 = 0
factorise this in pairs
5x(x-1) +3(x-1) = 0
(5x+3)(x-1) = 0

And yes, hopefully you can finish it from there.

Look here for more help
http://web2.0calc.com/questions/grouping-method-and-factorizing-quadratic-equations

MelodyMar 31, 2014

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The angle at the top of Alan's picture is the angle of depression.
The angle at the bottom is equal because they are alternate angles on parallel lines.

MelodyMar 31, 2014

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Serjio:
Give an example where you put observational learning into effect. What did you observe and what did you end up doing (or not doing)?

Hi Serjio,
I have observed that when it rains the washing gets wet so I have learned to take if off the line. Now do I get a lollypop?

MelodyMar 31, 2014

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reinout-g:
Bertie:
E5 must be 12.
It's not prime so it can't be at B5, it's divisible by 6 so can't go in C4 and it will be too big to go in A4 or D4.

Even though I'm currently at a point where I know you are right, at this point it still could've been at A3.

Be aware that in *15* they only mean the square which is diagonally at the right-bottom.

I am with reinout.
Why can't A3 be 12 Why does it have to be E5?
I'm sorry, I think that you have made a retraction and added a new answer.
I didn't notice.

So at this point E5 does not have to be 12 but B5 has to be 11.
I won't look at your logic - I will think about it first.
Thank you Bertie.

MelodyMar 31, 2014

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ohnonotmath:
Hello Melody!

0.15(1-x) = 0.3 + 0.33x
0.15 - 0.15x = 0.3 + 0.33x
(then I add 0.15x to both sides and subtract 0.3 from both sides)
0.15 - 0.3 = 0.15x + 0.33x
-0.15 = 0.48x
-0.15/0.48 = x
x = -0.3125 This is an exact answer, there is no need to round off.
?

Thanks for showing me how to set up the problem. Again it's one of those things I use to know but forgot over the years

So you are a mature aged student? What are you studying?
Have you collected your welcome message?
Melody

MelodyMar 30, 2014