Melody

921 Questions
34316 Answers

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Mathigon website

I just discovered a site called mathigon

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

Melody 2 avr. 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. lire plus ..

Melody 16 mars 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 lire plus ..

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Melody 15 mars 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

Hors sujet

Melody 13 mars 2022

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WELCOME BACK CPHILL !

Melody 11 févr. 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. lire plus ..

Melody 1 févr. 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 lire plus ..

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Melody 9 janv. 2022

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HAPPY BIRTHDAY CHRIS!

Melody 20 déc. 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 lire plus ..

Hors sujet

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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

Hors sujet

Melody 29 oct. 2021

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You have to take the log of both sides and the use log rules to simplify it.
i had written out a long answer but I lost it - my computer playsed up.

This interactive web page may help you understand logs better
http://www.mathsisfun.com/algebra/logarithms.html

also rules on manipulating logs are listed here
http://en.wikipedia.org/wiki/List_of_logarithmic_identities

Melody14 nov. 2013

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log base3 x^1/2 - long base3 y^2 - log base3 z^4?

0.5 * log ₃ (x / (y^4*z^8))

Melody14 nov. 2013

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solve the equation

1.2X = 72

Melody14 nov. 2013

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Solve the given nonlinear system by the addition method.
4x^2-2y^2=-2
x^2+4y^2=40

I'd do them as simultaneous equations solving by elimination method
multiply the 1st one by 2
add it to your second equation
You get
9x^2 = 36
solve
x=+-2
put each of these back into an original equation to get hte possible y values.

Melody14 nov. 2013

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what is sin c=1/n
n=1.34

it is an inverse sine or arcsine question
make sure your calc is set to degrees - there is probably a little D at the top of the screen.
then...

shift sin (1/1.34) =
ans is 48.268....
press the degrees minutes and seconds button and you get 48degrees 16minutes and 5.46seconds.

Melody14 nov. 2013

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OK so I"m having some difficulty with 10th grade ratios currently, this question in particular: (keep in mind that the / is a sign for what I think are ratios)
(x + 5)/16 = 32/5
Any help would be much appreciated!

The wording of ratios can be tricky.
Say you have 6L of diluted orange juice (that's orange juice and water)
If the concentration of orange is 1 in 3 then 1/3 is orange (the 3 represents the total)
The is 2L of pure orange mixed with 4L of water.
BUT
this means that the ratio of orange to water is 1 to 2 written as 1:2

If I say that the ratio 2:3 is equivalent to the ration x:12
I can solve this using fracions
2/3 = x/12
or
2/x = 3/12
or
12/3 = x/2
all of those would be correct.
But, 2:3 is not the same as 2/3
Do you get what I am trying to say?
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(x + 5)/16 = 32/5
so is your question actually
The ratio of (x+5) to 15 is equivalent to the ratio of 32 to 5. Find x?
(x+5) : 15 is equivalent to the ratio of 32 : 5

This is not the same as the fraction you set up BUT it can be solved using the fraction you set up.

(x + 5)/16 = 32/5
Now, do you need help with the actual algebra?
multiply both sides by 16*5 This will get rid of the fractions
Then expand the bracket
Then hopefully you can finish it.

Melody14 nov. 2013

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Yes of course, thank you guest for picking that up.

Melody13 nov. 2013

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4.5333 = 1/x(1-(1/(1+x^10))) ....find x
Multiply both sides by x
subtract 1 from both sides
multiply both sides by (1+10^x)
add 1 to both sides
I think you end up with

4.5333X ¹¹ + 4.5333X - 10 ¹⁰ = 0

And if you can solve this you are doing really well.

Melody13 nov. 2013

+118730

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Well, if you've got something like log 6 = x
you would just type in log 6

Yes but you need to know what the base is, your calculator can only handle base 10 (log) and base e ( ln )
Log ₁₀ 6 = 0.77815128....
Log _e 6 = 1.791759469.....
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If you'd have something like this
5log6 = x (or log5,6 that depends on country) NO, THESE ARE DIFFERENT THINGS

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5log6 means 5*log6 and that is how you enter it. (could be base 10 or base e or someother base, you need to know which one)

You are talking about change of base
log ₅6 which is worded as log of 6 base 5.
You can't do this on the calculator because it not in base 10 or base e, so you have to change it using change of base.

log ₅6 = log6 / log5 This will give the same answer no matter what base you use, so long as numerator and denominator have the same base.

log ₅6 = log6 / log5 = 1.113282753

I hope this clears things up a little.

This is a interactive web page that would be good for you to work through.
http://www.mathsisfun.com/algebra/logarithms.html

Melody13 nov. 2013

+118730

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Do you mean is y=2 a solution of ....?

Is 2 a solution to the following inequality: 7y + 4 > 20

Left hand side = 7*2+4 = 18
18 is not > 20
therefore y=2 is not a solution.

Melody13 nov. 2013