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

-10

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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

+118687

0

6ab-(12ab-4ab) = 6ab+ -1(12ab-4ab) there is an invisible 1 between the minus sign and the bracket.

= 6ab+(-1)*12ab+(-1)*-4ab

= 6ab-12ab+4ab

= you can do the rest.

This is the full explanation but you can just remember that if there is a minus sign outside the bracket like this one all the signs inside the bracket get changed when the brackets are removed.
For example
-(-a+6-2g) would become a-6+2g

I hope that you can learn from this.

Melody3 oct 2013

+118687

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Just divide then ignore the decimal part of the answer.

Melody3 oct 2013

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question doesn't make sense.

Melody3 oct 2013

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Your question is not complete
You need to say x = something. or f (something that isn't x)

Melody3 oct 2013

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-56 - (-34) = -56 - -34

if 2 + or - signs are so close to that you can put a circle around them without anything being in the way then,
if the signs are the same replace with a + that is ++=+ , and - - = +
if the signs are opposites replace with a - that is - + = - , and + - = -

you have 2 minuses so replace with a +

-56 + 34

Melody3 oct 2013

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V=5kg/10g/cm3

5000g/10g/cm3 = 500/cm3 but this doesn't make sense. You can't have cm3 on the bottom and no units on the top.

Melody3 oct 2013

+118687

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This is the sum of a geometric progression GP Do you know about those?

a=15
r=1.15
n= 200

s=a ( r^n - 1) / (r-1)

s= 15 * ( 1.15^200 - 1 ) / 0.15

sum of all the costs = 1.37 * 10^14 This is a very big number.

Melody3 oct 2013

+118687

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DEFINITELY -Do not put in t he zeros it is too easy to make a mistake!

the are 1000 mg in a gram.
(a milligram is smaller than a gram, so there will be more of them, so you need to multiple - I always go through this thought pattern when I am deciding whether to multiply or divide)

5.97 x 10ˆ(27) x 1000 mg

You can do this in your head, there are 3 zeros in 1000 so the exponent goes up by 3
5.9 x 10^30

or, on the calculator it is best to use the exponential button (REMEMBER NOT TO PUT THE 10x AS WELL)

5.9 exp 27 x 1000 = 5.9 x 10^30

Melody3 oct 2013

+118687

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Just think about each side side separately

There a 4 isosceles triangles, all the same, and 1 square base.

Hopefully you know how to find the area of the square.

Each triangle is 1/2 x base x height (the height is the slant height of the pyramid)

If you are not given the slant height you will need to work it out using the base the perpendicular height and pythagoras' theorem.

Melody3 oct 2013

+118687

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You don't use a common denominator when multiplying, that is only for adding and subtracting fractions.

You can do it straight off on a calculator.

If doing it by hand you will need to know that a positive times by a negative is negative.

then multiply the top for the top (numerator) 9x3

and multiply the bottoms for the denominator. 11*23

Melody3 oct 2013