Melody

921 Questions
34315 Answers

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Mathigon website

I just discovered a site called mathigon

https://mathigon.org/dashboard
read more ..

Melody Apr 2, 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. read more ..

Melody Mar 16, 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 read more ..

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Melody Mar 15, 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

off-topic

Melody Mar 13, 2022

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WELCOME BACK CPHILL !

Melody Feb 11, 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. read more ..

Melody Feb 1, 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 read more ..

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Melody Jan 9, 2022

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HAPPY BIRTHDAY CHRIS!

Melody Dec 20, 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 read more ..

off-topic

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Melody Nov 4, 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

off-topic

Melody Oct 29, 2021

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Ethan Bates:
The problem is: (3t + 4)^5
Instead of simply expanding, my instructor wants me to use Pascal's Triangle.

You have alreay had 2 good answers, I am offering a third.

140409 - Pascal's triangle.JPG

This is pascal's triangle - you are going to use the row where the 5 is the second number.

(3t + 4) ⁵= 1*(3t) ⁵*4 ⁰ + 5* (3t) ⁴*4 ¹ + 10*(3t) ³*4 ² + 10*(3t) ²*4 ³ + 5*(3t) ¹*4 ⁴ + 1*(3t) ⁰*4 ⁵

=(3t) ⁵ + 5* (3t) ⁴*4 + 10*(3t) ³*4 ² + 10*(3t) ²*4 ³ + 10*(3t)*4 ⁴ + 4 ⁵

MelodyApr 9, 2014

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helpneeded105:
What two numbers multiply to 600, and add to 17?
Everything Alan said is correct - There are no (real) solutions. I just want to talk about it a little more.

Original problem:
30+17a-20a^2

I am going to look at your original problems some more.

30+17a-20a ² = -20a ² + 17a +30

If you want to factorise this you need to look for 2 numbers that add to 17 and multiply to -20*30= -600
These numbers are not easy to find because thay are not rational. I could talk about this a bit more but I suspect Alan is correct when he said maybe the original question was
30+17a-20a^2 =0
in which case we have
-20a ² + 17a +30 =0
You can solve this using the quadratic formula. This will help you remember it.
http://www.youtube.com/watch?v=O8ezDEk3qCg
For you substitute in, a=-20, b=17 and c=30.
The unknown in your question is an a - usually it is an x.
Please do not get confused, the a in the formula is the number in front of the squared unknown. I mean the a in the formula is -20. do you understand what I am trying to say?

There are 2 solutions. They will be

(-17+sqrt(17^2-4*-20*30))/(2*-20))=
and

(-17-sqrt(17^2-4*-20*30))/(2*-20))=

These answers should be identical to Alan's answers. Mine are approximations, Alan's are exact.

MelodyApr 9, 2014

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Chris, you have made a small mistake. It is -3 not 3.

5s - 28 = -3
Add 28 to both sides
5s = 25
Dividing by 5 on each side gives us

s = 5

Once you fix your entry I will delete this one.

MelodyApr 9, 2014

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3_29_14:
andre surveyed a random sample of 30 students to find the heights of seventh grade students in his school. the mean of the data in his sample was 6103 inches. which of these is most likely the mean height of all the seventh grade students?

I think that some of your question is missing. Was it a multiple choice question?

MelodyApr 9, 2014

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HelP:
:o log 2x = log 10

Assuming that they are both the same base, 2x=10

MelodyApr 9, 2014

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Bre.20:
-x+2=4
x=

Subtract 2 from both sides and then think about it.
If you still don't get it, post again.

MelodyApr 9, 2014

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Hi Zahcarry123,

Thank you for your answer Zahcarry123, it is great when people get involved and answer (or ask) questions.

I just wanted to mention these things.

1) Your last answer is better but it is an approximation. Why would you approximate an answer when it can easily be written exactly? (either as a fraction or as a recurring decimal)

2) Where is your working - you are supposed to be helping jumper2332 to understand.

3) If you were a member you would be able to edit/delete incorrect posts so that you would not have to leave incorrect answers on tha page. This is just one of the reasons that you may like to join up.
Here are some more reasons;
http://web2.0calc.com/questions/become-a-member-why-would-you-want-to Just highlight the address - left click - choose 'goto'. It will open in a new page.

MelodyApr 9, 2014

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smitty:
which rule can be used to find the nth term af the following sequence? 1.25,1.5.1.75,2

Well
1.5-1.25=0.25
1.75-1.5=0.25
2-1.75=0.25
So it is an Arithmetic progression.
So you must have to use the nth term of an AP formula.

If you need more help try looking here.
http://www.mathsisfun.com/algebra/sequences-sums-arithmetic.html

MelodyApr 9, 2014

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Zahcary123:
:D Its is 450

Do you want to rethink that Zahcary123?

MelodyApr 9, 2014

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+9

Hi all,
Great answers were provided by reinout-g, CPhill, Alan, guest, A person (really?), -D and Anonymous4338. Thanks guys.
It has been very quiet, Easter is looming so I guess it will get even quieter for a while.
I did learn what the answer to life and all great mysteries is, almost anyway. I guess that is not so bad for one day.
http://web2.0calc.com/questions/math_1702
Night all,
Melody.

MelodyApr 8, 2014