Melody

921 Questions
34315 Answers

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1731

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+118690

Mathigon website

I just discovered a site called mathigon

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

Melody 2 Apr 2022

-10

595

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+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

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1403

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+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

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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

और पढ़ें ..

विषय से परेे

Melody 13 Mar 2022

-6

836

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+118690

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. और पढ़ें ..

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 और पढ़ें ..

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Melody 9 Jan 2022

-8

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HAPPY BIRTHDAY CHRIS!

और पढ़ें ..

Melody 20 Des 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 और पढ़ें ..

विषय से परेे

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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

विषय से परेे

Melody 29 Okt 2021

+118690

0

Guest:
how to show the above trinomial will not give prime numbers for very many values of x w/o having to plug in a lot of values starting from 0

Re: trinomial x^2+x+31

I am not sure what you mean. 'Not very many' is not very precise.
If x=0 the value will be 31 which is prime number.

Melody9 Des 2013

+118690

0

Guest:
Find the angle θ between the given vectors to the nearest tenth of a degree.
U = −5i + 7j, V = 8i + 3j

It has been a long time since I worked with vectors but I think this is right.

The angle between the x axis (on the right hand side) and V is tan ^-1 (3/8) = 20.556 degrees

The angle between the x axis (on the left hand side because of the negative sign) and U is tan ^-1(7/5) = 54.462 degrees

So the angle between them is 180 - tan ^-1 (3/8) - tan ^-1(7/5) = 104.981 = 105.0 degrees (correct to 1 decimal place)

Melody9 Des 2013

+118690

0

alberto:
what -31+15=16
right

Think of it like this

The temperature is -31 degrees, it gets warmer by 15 degree, has it reached 0 yet or is it just closer to 0 (that is, less negative)?

It would have to warm up by 31 degrees before it got to 0 so it must just be 'less negative'.

So the answer is negative but closer to zero than -31.

31-15=16
so
-31+15 must be -16

Melody9 Des 2013

+118690

0

Helpme123:
what is 8^(3) x 16^(4) simplified?

You could just do it on your calculator but I assume that that is not the idea.

Why don't you start by saying

8 ³ * (2*8) ⁴= 8 ³ * 2 ⁴ * 8 ⁴

Can you take it from here?

Melody9 Des 2013

+118690

0

Michaela:
Find the LCM for 3 and 8

Hi Michaela,
To find the LCM (lowest common multiple)
Choose the biggest number, which is 8
write down the multiples of 8
8,16,24,32,....
then look at them and find the smallest one that is also a multiple of 3
-----------------------------------
If this is a bit difficult, you could also write down the multiples of 3
3,6,9,12,15,18,21,24,27

The smallest number that is in both lists is the answer!

Melody9 Des 2013

+118690

0

The square on the hypotenuse is equal to the sum of the squares on the other two sides.
Is that what you meant?

Or,
did you meant SOHCAHTOH
which stands for sine=opp/hyp, cos=adj/hyp, tan=opp/adj

Or
did you mean 'some old hags can't always hide their old age"
where the first letters stand for sine=opp/hyp, cos=adj/hyp, tan=opp/adj

Or did you mean something else?

Melody9 Des 2013

+118690

0

fred:
True or False Some cubic equations have no real roots and explain

Hi Fred,

All cubic equations have to have at least 1 real root. (unless you place restriction on the domain)

consider y=ax ³+bx ²+cx+d

As x approaches positive infinity the ax ³ term will have far more impact on the answer than any of the other terms. If a is positive, y will approach infinity.
As x approaches negative infinity the ax ³ term will have far more impact on the answer than any of the other terms. If a is positive, y will approach negative infinity.
(If a is negative it will be the other way around)

In order to get from y= -infinity to y= +infinity the curve must go through y=0 at least once. So there must be at least one real root.

do you understand what I am trying to say?

Here is a web page if you would like to take a look.

http://en.wikipedia.org/wiki/Cubic_function

Melody9 Des 2013

+118690

0

Helpme123:
What is the HCF of 120 and 42 and how do I find it out?

One good way is as follows.
Choose the smaller number which is 42
1*42=42 so 1 and 42 are factors and 42 is the biggest factor of 42. Does 42 go into 120? NO so we'll look for the next biggest factor of 42

2*21=42 so 2 and 21 are factors and 21 is the next biggest factor of 42. Does 21 go into 120? NO so we'll look for the next biggest factor of 42

3*14=42 so 3 and 14 are factors and 14 is the next biggest factor of 42. Does 14 go into 120? NO so we'll look for the next biggest factor of 42 (4 and 5 don't go into 42)

6*7=42 so 6 and 7 are factors and 7 is the next biggest factor of 42. Does 21 go into 120? NO so we'll look for the next biggest factor of 42

Since there is no numbers between 6 and 7 we have now found all the factors of 42 so the next biggest one must be 6
does 6 go into 120? YES
So 6 must be the Highest common factor.
---------------------------------------------------

It might have been easier just to write down all the factors of 42 then put them in order and then look which ones go into 120 and select the biggest one.
1,42,2,21,3,14,6,7
1,2,3,6,7,14,21,42
The biggest one that goes into 120 is 6
So 6 must be the Highest common factor.

Melody9 Des 2013

+118690

0

oman:
soppose a new breed of rabbits triples its population every month,if there are three rabbits after one month the population is after n months would be 3 to the power of n " please i need help.

I am not sure what your question is Oman but I will talk about the situation that you are describing

After 1 month, when n=1 Population=3=3 ¹
After 2 months when n=2 Population=3*3=3 ²
After 3 months when n=3 Population=3 ²*3 = 3 ³
can you see the pattern?
for any number of months 'n' the population will be 3 ⁿ

I hope that helps.

Melody9 Des 2013

+118690

0

1/5(a+3)=1/3(5-a)

Hi Sam
First I'm just going to talk about the left hand side LHS
it would be good if you realize that
1/5(a+3) = 1/5 * (a+3)/1
if you write this as an upright fraction you will be able to see that it isthe same as 1*(a+3) / (5*1) = (a+3)/5
so your equation would more usually be written as
(a+3) / 5 = (5-a) /3
Please write these fraction upright, it will make it much easier to see what is happening

3 and 5 are both denominators and they have no common factors and 3*5=15
If you multiply both sides by 15 then the denominators will cancel out and there won't be any fractions any more.
Then you just expand the brackets and solve like any other non-fraction equation.
Can you do the rest yourself?

Melody9 Des 2013