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

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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

+118690

0

Warren:
3cos2(x)=3sin^2+2

Your question soesn't really make sense Warren
do you mean this?
3cos(2x)=3sin ²(x)+2

Melody10 dic 2013

+118690

0

southdakota:
the algebra question is asking me to solve for x

9^x-1=4

Can you start it?
You will get to a point where 9^x = some number

Whenever you need to find the value of an exponent, you have to take the log of both sides.
Then you will need to use one of the log identities on this page to help solve it.
http://en.wikipedia.org/wiki/List_of_logarithmic_identities

Have a go it it from here.

Melody10 dic 2013

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0

mathmathmath:
the problem is:

Find the time required for money invested at an annual rate of 4% to double in value if the investment is compounded continuously. Round to the nearest hundredth of a year.

please help

You have to give the initial amount of money a value. It doesn't matter how much because $5 will double in the same amount of time as $1000 will double.
I'm going to start with $1 because it is easiest and I need to work out how long it will be before I have $2.

Inially I have $1
After one year I have $1*1.04 = 1.04 (dollars)
After 2 years I have 1.04*1.04 = 1.04 ²
After 3 years I have 1.04 ²*1.04 = 1.04 ³

After n years I have 1.04 ⁿ dollars
The answer will be given by the equation

2=1.04 ⁿ
Since it is the exponent that you need to find, you wil need to take the log of both sides to get the answer.

Try to finish it by yourself.

Melody10 dic 2013

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0

San Takisojotando:
pai che no do se qui pu ti na di ti cu o xi zen mai do na. Chu ce nu te qi on nu pe jo ma vug xin zep po?

234(23*12) x/12=?

Hi Lmao, I don't understand your words but this is the answer to your question. The 12's cancel out.

= 234*23*12*x / 12
= 234*23x / 1
=5382x

I tried to translate this.
One translator said it was Gallacian
the other said it was Romanian
Neither translation made any sense.

Can anyone on the forum tell me what language this is, or what Lmao is trying to explain?

Melody10 dic 2013

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0

jimmy:
what percentage is 20,000 of 550,000

you write it as a fraction first.
then you multiply by 100 to turn it into a percentage (don't forget the percent sign)

Melody10 dic 2013

+118690

0

StuckWithMath:
I'm currently stuck with my college math. i hate to do this but i need help with four questions

A. SOLVE FOR X

log(4)x+log(4)(x-15)=2

B. SOLVE FOR X

ln(x+1)=0

C. SOLVE FOR X

9^(x+1)=4

D. SOLVE FOR X

(3-2x)-4(2+x)=4x

There is a lot of questions here.
ok I'll start with d.
(3-2x)-4(2+x)=4x
expand out the left hand side and simplify it by adding like terms.
move the 'lots of x' to the right side - do you know how to do that? (remember it is opposite so if it was +20x then you would -20x from both sides.)
lastly you divide both sides by the number in front of the x.

question C you have to take the log of both sides to solve it.
then look for an identity you can use from this web page
http://en.wikipedia.org/wiki/List_of_logarithmic_identities

question B consider this
log _xy = 0
then x ⁰ = y
what does y have to equal?
This is an interactive web page that takes an introductory look at logs. You probably should work through it.

question A is the hardest one
log(4)x+log(4)(x-15)=2
If you mean exactly what you have written then the question is
xlog4 + (x-15)log4 = 2
You can collect the lots of log 4 on the left eg 6x + (3+1)x = (6+3+1)x This is just an example to give you a hint.
Then you can solve it like any equation. Just remember log4 is just a number.

That's enough help for starters.
Get back to me and show me what you have acheived by yourself.

Melody10 dic 2013

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Guest:
:geek: In Fraction form, what is 28 divided by 26

Well, how many times does 26 go into 28?
Or to put it a different way
If you have 28 lollies and you divide them amoung a class of 26 students, How many whole lollies does each child get?
The answer is the whole number part.

How many are left over? The left over number goes over the number you divided by to get the fraction part.

Now you can simplify the fraction bit by dividing the top and bottom by 2.

You try to do it and post your answer so that I can see it.

Melody10 dic 2013

+118690

+2

lynda:
Explain why y\this works. Assume the person is working 40 hours a week.

Explain why what works?

Melody10 dic 2013

+118690

0

2a+2b

Is this a question?

Melody10 dic 2013

+118690

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Hi Professor Lopez,
You have differentiated the function correctly but you have not stated the domain.
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Give the Domain of the function g(x)=1/x

Hello 'Hello'
Do you know what a domain is?
It is all the values that x can be, does that help?
What you really need to do is think about what x cannot be first.

You try to answer this, what can x NOT be?
Then try to write the domain which is what x can be.
come back to me with your answer.

Melody10 dic 2013