Melody

921 Questions
34316 Answers

+1

1

1742

2

+118730

Mathigon website

I just discovered a site called mathigon

https://mathigon.org/dashboard
lire plus ..

Melody 2 avr. 2022

-8

610

1

+118730

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. lire plus ..

Melody 16 mars 2022

-2

8

1481

5

+118730

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 lire plus ..

●●●●●

Melody 15 mars 2022

-3

873

3

+118730

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

Hors sujet

Melody 13 mars 2022

-4

850

3

+118730

WELCOME BACK CPHILL !

Melody 11 févr. 2022

-5

719

2

+118730

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. lire plus ..

Melody 1 févr. 2022

-7

888

11

+118730

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 lire plus ..

●●●●●●●●●●●

Melody 9 janv. 2022

-6

1

997

3

+118730

HAPPY BIRTHDAY CHRIS!

Melody 20 déc. 2021

+5

16

5574

9

+118730

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 lire plus ..

Hors sujet

●●●●●●●●●

Melody 4 nov. 2021

-9

1093

1

+118730

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

Hors sujet

Melody 29 oct. 2021

+118730

0

if a diameter of a pipe is 200mm
the velocity is 0.25m square per second, what is the length of the pipe? I know L=V/Pirexponent 2
But I don't understand how people get 7.958 m when i get 0.0000079577471546

I used to find the cross sectional area: (Pi/4)* D (200^2).
then 0.25 was divided by the result to get 0.0000079577471546.

other gor a positive result 7.958.m
------------------------------------------------------------------------------------------------------------------
first i will admit that i have no knowledge to this stuff.
Why does the pipe have to be any particular length? This is a serious question. Can you answer it?
BUT
could it be that the 200 is in mm and the 0.25 is in metres/s ²
so it 200mm is put in as 0.2m I think your quandrey will be overcome.

Melody17 nov. 2013

+118730

0

odds of hitting 1/38 chance 3 times in a row

1 in 38 ³ = 1 in 54872 = 1/54872

or

1 to 54871 = > 1 : 54871

Melody17 nov. 2013

+118730

0

you will need to give more information than that. I don't understand.

Melody17 nov. 2013

+118730

0

What is 4.60x10^-14 / 9.11x10^-31 =

= [ 4.60x10 ^-14 / 9.11 ] x 10 ^-31

=5.049 * 10 ^-46 (correct to 4 significant figures)

The real meaning of this type of question is often ambiguous. You really do need to use bracket.

Melody17 nov. 2013

+118730

0

Melody17 nov. 2013

+118730

0

6a^23b^6/4a^3bc^3

=( 6a ²³b ⁶/4) * a ³bc ³

This is the question that you have asked. Is it what you really meant?

Melody17 nov. 2013

+118730

0

int(sin(x^2), x)

I don't know this notation at all
Is it possible that it means
Find the integral of sin ²x with respect to x ?

I will answer this one anyway

sin ²x = 1 - cos ²x

sin ²x = 1 - [ (cos(2x) + sin ²x ]

sin ²x = 1 - (cos(2x) - sin ²x

2sin ²x = 1 - (cos(2x)

sin ²x = 1/2 - [cos(2x) / 2]

integral of sin ²x = x/2 - sin(2x)/4

integral of sin ²x = [2x - sin(2x) ] / 4

Now, is that what you wanted?

Melody16 nov. 2013

+118730

0

6 factorial is written as 6!

And
6! = 1*2*3*4*5*6 = 720 (they are multiply signs)

It is used a real lot when working out probabilities.

The is even a factorial button on your calculator ! (you probably have to press 'shift' first.)

Melody16 nov. 2013

+118730

0

Pi is an irrational number. It can not be expressed exactly as a fraction or as a decimal - not even a recurring decimal.

Melody16 nov. 2013

+118730

0

the base on a baseball diamond are 90 feet apart. how far is it from home plate to second base?

A base ball diamond is a square isn't it?
so all the angles are 90 degrees
you have the 2 short sides, so I think you want the hypotenuse.
Use Pythagoras's Theorem.

Melody16 nov. 2013