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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609

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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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871

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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

+118725

0

vicky:
2.5 km. how many metres is that ?

Multiply by 1000

MelodyFeb 9, 2014

+118725

0

vicky:
2.5 km. how many metres is that ?

multiply it by 1000

MelodyFeb 9, 2014

+118725

0

ashwin_7:
cube root of 72.9

A cube root is a power of 1/3 so
The power of symbol is ^ or x ^y

just press

72.9 ^ (1/3) =

MelodyFeb 9, 2014

+118725

0

Jessica:
:shock: hi

Halo kepada anda.
Anda boleh beritahu saya apa Bahasa aku menulis ini?

MelodyFeb 9, 2014

+118725

+14

Good evening everyone,
Another very quiet day today.
However, great answers were forthcoming from Rom, DavidQD, gibsonj338 and guest. Thank you.
I used the character map that 'I like Serena' told me about today. It was really good. Thanks ILS

A lot of people, including myself, originally think that the message system doesn't work.
This is because messages seem to 'get stuck' in the outbox.
The system does work, the messages will stay in your outbox until the recipient opens it. The message will then move to 'sent messages'.
While the message is in the outbox, you can edit it and you can delete it.
If you delete a message that was already in the outbox then the recipient will still receive a message. The message will tell them that you had sent mail but that you had already deleted it.

If you choose to, you can be notified of new private messages.
To do this go to the User Control Panel and choose the Board Preferences tab. Then select "notify me of new private message".

Enjoy the rest of your weekend,
Melody.

MelodyFeb 9, 2014

+118725

+6

MelodyFeb 9, 2014

+118725

+8

MelodyFeb 9, 2014

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Guest:
a2=b2+c2-2(bc)cosA

This is cosine rule. It is probably better written like

a ²=b ²+c ²- (2bcCosA)

That way you are less likely to make a mistake when you work out your answer.

MelodyFeb 9, 2014

+118725

0

Guest:
no, a2= c2-b2

a ²=c ²-c ²
Hi Guest,
You are right,
This could easily have been Pythagoras Theorem
And often with Pythagoras the hypotenuse is called c
In which case your answer is completely correct.
BUT
The hypotenuse does not have to be called c.
It can be called anything.
This is important for you to understand and remember.

By the way, I used the 'sup' button above the smilies to get the indices where they belong. 'sup' stands for superscript.

MelodyFeb 9, 2014

+118725

0

lolkbye:
3.00x10^8/(7.91x10^10)

Great answer gibsonj338

I'd do it like this

3/7.91 * 10 ⁸ * 10 ^-10

0.379267 * 10 ^-2

3.79267 * 10 ^-1 * 10 ^1-2

3.79267 * 10 ^-3
or
0.00379267 ( correct to 6 significant figures)

Which is exactly the same answer as gibsonj338 got.

MelodyFeb 9, 2014