Melody

921 Questions
34315 Answers

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1731

2

+118690

Mathigon website

I just discovered a site called mathigon

https://mathigon.org/dashboard
और पढ़ें ..

Melody 2 Apr 2022

-10

596

1

+118690

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. और पढ़ें ..

Melody 16 Mar 2022

-4

1403

5

+118690

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 और पढ़ें ..

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Melody 15 Mar 2022

-5

858

3

+118690

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

और पढ़ें ..

विषय से परेे

Melody 13 Mar 2022

-6

836

3

+118690

WELCOME BACK CPHILL !

Melody 11 Feb 2022

-6

707

2

+118690

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. और पढ़ें ..

Melody 1 Feb 2022

-8

870

11

+118690

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 और पढ़ें ..

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Melody 9 Jan 2022

-8

1

981

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+118690

HAPPY BIRTHDAY CHRIS!

और पढ़ें ..

Melody 20 Des 2021

+4

1

5471

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+118690

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 और पढ़ें ..

विषय से परेे

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Melody 4 Nov 2021

-10

1077

1

+118690

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

विषय से परेे

Melody 29 Okt 2021

+118690

0

[quote="CPlusHris"][input]4.3*10^-3=10.2(sqrt(2y*(147.83-51.9[/input] Estimate the following of y correct to one significant figure without using a calculator.

I have tried several times to try and solve this. I ended up with 0.016 as an estimate using the following method.

1. Round off: 4.0* 10^-3=10(sqrt(2y*(150-50)
2. Put 4.3*^-3 into standard form: 0.0043

Working out
0.0040=10(sqrt(2y*(150-50)

0.0040=10(sqrt(2y*100)

0. 00040=(sqrt(2y*100)

0.00000016=2y*100

0.0000000008

8 * 10^(-10)

Just a couple of little errors can make a big difference!

The actual answer is 9 * 10^(-10) Correct to 1 significant figure.

So your answer (and mine) does not quite have the accuracy that you were asked for.
But I still think that it is a sensible estimate.

Melody22 Des 2013

+118690

0

CPlusHris:
Does -|-8|-|-3| evaluate to 5 or 11?

Hi CPlusHris

This is -(8) - (3) = -8-3 = -11

why don't you try this one

-|8-5|+|-6+1|=?

Melody22 Des 2013

+118690

0

Hi Tayfuntan,

One source of confusion is that t and T are totally different things
T is a constant and t is a variable.
131222 Latex answer integral.JPG

I then used Wolfram Alpha calculator to solve

http://www.wolframalpha.com/input/?i=solve+%2836.4%2B6*10%5E-3T-2*10%5E5*T%5E-2%29%28T-600%29+%3D94258+over+the+real+numbers

There are 4 answers.

Melody22 Des 2013

+118690

0

Please show me what you have tried.
Maybe with an attachment.

Melody22 Des 2013

+118690

0

VIPIN:
HOW TO FIND SLOPE OF TRIANGLE

Hi Vipin,
Do you want to try and re-phrase your question? It really does not make any sense at the moment.
Sorry.

Melody21 Des 2013

+118690

0

Peter A Boldtg3g:
solve the resolution of two forces acting on a point at a specific angle

Hi Peter,

You need to get the x and y components of each of the forces
Then Add the x components to get the resultant x force
Add the y components to get the resultant y force

once you have the resultant x and y forces you can then put them together to get the resultant force and angle direction.

Look at this you tube clip.

http://www.youtube.com/watch?v=e-d-aVvx5RA

Melody21 Des 2013

+118690

0

lilg96:
how much heat is required to raise the temperature of 235g of iron from 22.5 C to 234 C?

Hi Lilg
i'll will start by saying that I am no chemist.
I googled your question and the exact same question (with the answer) was in a number of places

It seems that
heat required = Mass * specific heat of iron * increase in temperature
You do need to check that the units are compatible

Depending on which web page I look at, the specific heat of iron is between 444 and 460 [J/(KgDegrees)] I don't know why the values are different.

This is a snip of an answer.
131221 heat needed for temp change.JPG
This is a 2nd answer
131221 heat needed for temp change2.JPG

There you go, take your pick.

Melody21 Des 2013

+118690

0

Mighty:
A race horse took 2 2/5 minutes to run 1 1/2 miles. How long would it take the horse to run one mile?

Hi Mighty,
There is a couple of ways to do this.
----------------------------
If you just think about the units, you want minutes/mile
So, if you take the number of minutes and divide it by the number of miles, you will have your answer.
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another way to do it would be to realise that if you divide 1 and a half miles by 3 you get 1/2 a mile
so if you divide 2 2/5 by 3 you will find out how many miuntes to run a half mile.
What would you do then?
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Melody21 Des 2013

+118690

0

Mighty:
A meter stick standing vertically casts a shadow 1.5 meters long on the ground. At the same time, a nearby tree casts a shadow 9 meters long on the ground. About how tall is the tree?

Hi mighty,
This is a similar triangle question. It is not particularly difficult, you don't need to use trigonometry or pythagoras or anything like that.
I want you you to try answering it yourself (Hint:draw the 2 triangles).
Get back to me with either your answer or with an explanation of what you have attempted.
That would be good.

Melody21 Des 2013

+118690

0

Guest:
find the amount of time required to double an amount at 4.44% if the interest is compounded continuously

The formula is
S=A(1+i) ⁿ
where S is future value
A is present value
n is the number of compounding time periods
i is the interest rate per time period.

Now there are some problems with your question.
First I suppose i can assume that you meant 4.44% per annum. But I don't think that you really mean that it compounds continuously.
Maybe it compounds daily or weekly or monthly or yearly or some other time period
This needs to be specified before the question can be answered any further.

Melody21 Des 2013