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

-5

859

3

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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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870

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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 ..

Fuera tema

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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

+118691

0

Excellent. I'll give you another question tomorrow.

Melody4 ene 2014

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0

quak:
find the rate compounded semiannually if $16,000 accumulates to $25,000 in 3 years and 6 months.

Show me what you know or what you have tried so far.
for example, what formula are you going to use and what values are you going to give the letters?

Melody3 ene 2014

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0

ok random,
The first 2 were well done.
I'll try to show you what compound interest and nets of bananas have in common.

Bananas
2 bananas per net
12/2 = 6 nets per dozen

$4.08 per dozen
r = $4.08 / 6 per net

We want 5 dozen bananas
n = 5 * 6 = 30 nets (that is 5 dozen and 6 nets per dozen)

Compound Interest
2 months per 'net' In this case a net is the compounding period of time. There are 2 months in each 'net'.
Interest is stated per year, there is 12 months in a year, so you can think of a year as a dozen months
12/2 = 6 'nets or compounding periods' per year

Interest rate is 0.072 per year (12 months)
r = 0.072 / 6 per 'net' or compounding period. (the interest rate for 2 months has got to be less than the interest rate per year! )
r = 0.012 (This is the interest rate per 2 months (per net)

we want 8 years worth of interest.
There are 6 compounding periods (nets) every year. so there must be 8 * 6 = 48 compounding periods (nets) in 8 years
n = 8 * 6 = 48

THINK ABOUT IT HARD FOR A WHILE THEN HOPEFULLY YOU WILL UNDERSTAND
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Now study this question, then when you think that you have it try thiis one without looking back.
Look back and double check that it is right before you post your answers.

Tony invested some money at 4.2% per year. It is compounded every 2 months (each 'net' holds 2 months) for 4 years.
a) Write 4.2% as a decimal
b) How many 'nets' of 2 months are there in a year . Use this number to get the next 2 answers.
c) r is the interest rate per compounding period (per net) Find r (show working)
d) n is the total number of compounding periods (nets) . Find n (show working) and put n=

Give it your best Random - don't cut corners - and think really hard.
Good luck.

Melody3 ene 2014

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0

nikosnikitakis:
how can i find the division 24a+11/13a+13

Should there be any brackets?

Melody3 ene 2014

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0

bahrian:
how to use tangent inverse

Hi Bahrain,
Can you explain what you want better? I don't understand your question.

Melody3 ene 2014

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0

analia:
per c'vlera te parametrit m ekuacioni 2x^2-x+(5-m)=0

Albanian to English

for what use the parameter m equation 2x ² - x + (5-m) =0
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I don't really understand what you are asking but I have solved the equation for x. I hope this is helpful.
Unë vërtetë nuk e kuptojnë se çfarë ju jeni duke kërkuar, por unë kam zgjidhet ekuacioni për x. Unë shpresoj se kjo është e dobishme.
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x = [-b+-sqrt(b ² - 4ac)] / (2a)

a = 2, b = -1, c = (5-m)

x = [ --1+- sqrt(1 - 4*2*(5-m) ] / 4

x = [ 1 +- sqrt( 1 - 8(5-m) ] / 4

x = [1 +- sqrt( 1-40+8m) ] / 4

x = [ 1 +- sqrt (8m - 39) ] / 4

Melody3 ene 2014

+118691

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okay I misunderstood, I thought you wanted to use up the interest as well as the principal in the 10 years.

You are also correct in thinking that you have turned a mole hill into a mountain.

I assume your logic is correct since you got the right answer but how about thinking of it like this.

You want to get $250 interest every 6 months because you will take that out and your principal will remain untouched.

I = P r t (You can use simple interest since you are only talking about 1 time period)
r = 0.025
t=1 (time period)
I = $250
P is unknown

250 = P * 0.025 * 1
P = 250 / 0.025
P= $10000

This is a little more straight forward I think.

Melody3 ene 2014

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Hi Duck908,

Thanks for the feedback. I really appreciate it.

Melody.

Melody3 ene 2014

+118691

0

Hi randomstatistics,

This is an interesting question, and I like that fact that you have already had a good play with it.
I assume that $10000 is your answer is that right?
Have you looked at this logically to see if it could be right?
You are only going to get $250 twice a year for 10 years.
If you got no interest at all, how much money would you need in your account?
How much money do you want in the account at the end of 10 years. I am assuming that you didn't want any. Is that what you meant?
You have answered a good question, I am just not sure that it is the question that you intended. Do you know what question you have answered?

Melody3 ene 2014

+118691

+6

kitty<3:
Sure, I checked these already:

Thanks Kitty.
PUZZLE 5
5, 3, 3, 10, 25 --magic number 325
You have to use the numbers (not necessarily all of them) to make the magic number 325.
You are allowed to use + - x and divide and you can use brackets
I have found 2 answers, and there might be more. If you can find 1 of them why don't you post it and show us how clever you are.
I would really like to get some games like this going, but I need people to join in!
'
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NOTE: This is a totally separate question. (From Kitty<3)
And just a random True or False mindbender:)
Which of the below statements is true, and which is false? Why? (This question relates to just 4 questions that have been answered T or F)

The number of false statements is one.
The number of false statements is two.
The number of false statements is three.
The number of false statements is four.

This was really tricky Kitty. I think I've got the answer. There is only 1 correct answer. Can anyone else work it out ??

Melody3 ene 2014