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جوري
12-24-2010, 07:40 PM
I love numbers and not sure why.. so created this thread for interesting math/physics problems to go into.. I have nothing to contribute (I am of a simple mind) but I do enjoy learning so please share what you've learned..



:w:
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GuestFellow
12-24-2010, 08:52 PM
:sl:

I don't mind maths but I hate probability and drawing tree diagrams. I used to spend half an hour drawing tree diagrams and it drove me mad.
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جوري
12-24-2010, 09:11 PM
go ahead share a nice mathematical problem with us if you don't mind..

:w:
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Perseveranze
12-24-2010, 09:33 PM
Asalaamu Alaikum,

This gives me bad memories alright
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جوري
12-24-2010, 09:38 PM
format_quote Originally Posted by Perseveranze
Asalaamu Alaikum,

This gives me bad memories alright
oh how come? I really enjoyed my calculus class back in undergrad I had an awesome professor and she broke things down so that a dummy can understand.. it is interesting to note that I scored higher in calculus than pre-calculus because of her.. she was a gentle patient lady.. (of course I remember positively nothing of calculus) I can barely do basic math now but it would be nice if folks would share of their course work.. it is really a shame that we don't keep the knowledge of all the disciplines we learned.. but I'd like to think that it would come back in a flash under the right circumstances. ..

lol the other day I was remembering (SOHCAHTOA) from grade school and I googled it and found this youtube video..



I was like oh my God that was ages and ages ago :haha:
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GuestFellow
12-25-2010, 08:28 PM
format_quote Originally Posted by τhε ṿαlε'ṡ lïlÿ
go ahead share a nice mathematical problem with us if you don't mind..

:w:
:sl:

I have a cousin who is going to be studying a Maths Degree through Open University. He is alright at Maths but not brilliant.

What advice would you give to someone who is studying Maths?
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جوري
12-25-2010, 08:32 PM
format_quote Originally Posted by Guestfellow
I have a cousin who is going to be studying a Maths Degree through Open University. He is alright at Maths but not brilliant. What advice would you give to someone who is studying Maths?

I should be seeking advise from people studying math not dispensing with it.. nonetheless I think the best way to master any craft is to do it everyday and not let it pile up on you.. maybe you can invite him here so he can do his coursework live and teach us a little something?

:w:
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Woodrow
12-25-2010, 08:48 PM
format_quote Originally Posted by Guestfellow
:sl:

I have a cousin who is going to be studying a Maths Degree through Open University. He is alright at Maths but not brilliant.

What advice would you give to someone who is studying Maths?
Change to literature before it is too late.

I am an avowed math hater. Oddly nearly every college course I ever took was very heavy into math. It seemed that Calculus was going to become my native language at one point. But oddly I enjoy non-Euclidean Geometry. Probably because nobody could ever prove how stupid I was in regards to math when I started parroting some neat theorems.

Just now trying to find some of the old theorems I was taught I came across this.


The theorems of Ibn al-Haytham, Khayyam and al-Tusi on quadrilaterals, including the Lambert quadrilateral and Saccheri quadrilateral, were "the first few theorems of the hyperbolic and the elliptic geometries." These theorems along with their alternative postulates, such as Playfair's axiom, played an important role in the later development of non-Euclidean geometry. These early attempts at challenging the fifth postulate had a considerable influence on its development among later European geometers, including Witelo, Levi ben Gerson, Alfonso, John Wallis and Saccheri. All of these early attempts made at trying to formulate non-Euclidean geometry however provided flawed proofs of the parallel postulate, containing assumptions that were essentially equivalent to the parallel postulate. These early attempts did, however, provide some early properties of the hyperbolic and elliptic geometries.

SOURCE


Hmmm, interesting
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Samiun
01-02-2011, 04:34 AM
:sl: I failed to answer a Sine Consine Tangent question during one of my important exams, it was actually a dumb mistake. I didn't minus the Square Root with another Square Root, instead, I convert the square root and minus them together.
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tigerkhan
01-02-2011, 05:08 AM
i love mathematics during my school times. infact i loves science subjects physices, chemistry biology, mathematics that times...ok good memory to share. one day my cousin visit us and i challange him i answer ur qst. i was in i think 4-5 class. he ask 3+3*3= ? i calculate 3+3=6 and then 6*3=18, i answer 18.... he laughed..i say y, i am rite..he say no... i confused alot bcz i forgot at that time whenever there is addition and multiplication both in a expression, u should multiply first and then add.....so correct answer was 3*3=9 and 9+3=12...lol
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Hugo
01-04-2011, 04:18 PM
format_quote Originally Posted by Guestfellow
I have a cousin who is going to be studying a Maths Degree through Open University. He is alright at Maths but not brilliant. What advice would you give to someone who is studying Maths?
Maths is like most subjects if not all that you have to master the basics otherwise you quickly get bogged down in the algebra or arithmetic. But the key is three fold:

1. Make sure you have understood the basics. This means going to lectures, tutorials and reading notes and books - for examples, its is common for students to get stuck on surd's but one often finds that those same students did not learn thoroughly the basic rules of indices.

2. Practice, do as many examples as you can and DO NOT skip over the simple ones. As an illustration it would be foolhardy to try an exercise on surd's before doing lots of simpler exercises using the laws of indices.

3. Do the examples without help if you can and indeed only call for help after you have struggled for some time, that way the concepts and processes will become your own. If you immediately call for help you are just being lazy and this attitude will make things harder each time you move up the ladder.

Finally, always remember that not everything is simple and can be understood first time round and ALWAYS will require effort and perverseness from you. If you want everything to be easy then go an do something else.
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GuestFellow
01-04-2011, 05:31 PM
^ Thanks! My cousin will find that useful.
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IAmZamzam
01-05-2011, 08:31 PM
I am seriously learning disabled in math (technically in all matters of calculating nonverbal symbols in sequential patterns: it's the same reason I can't comprehend sheet music or that blasted pseudo-mathematical style of argumentation philosophical types use when they want to be particularly pretentious instead of just writing out a danged syllogism). It's my only real intellectual weak spot. I'm still not sure how I made it through high school; the only explanation I have is that my math teachers must have given me more points for effort than they were probably allowed to.

I do, however, know one neat trick, and one only: when you multiply any number by nine and add up the digits of the result, it will always leave you with nine. (Or if there are still multiple digits left in the result then just add them up, and so on, until there's only one left, and that one digit left will always be nine.) Probably I haven’t explained this very coherently so let me give you a few examples:

9*5=45.
4+5=9.

9*26=234.
2+3+4=9.

9*747=6,723.
6+7+2+3=18.
1+8=9.

9*12,345=111,105.
1+1+1+1+0+5=9.

9*54,321=488,889.
4+8+8+8+8+9=45.
4+5=9.

9*8,675,309=78,077,781.
7+8+0+7+7+7+8+1=45.
4+5=9.

Care to take it into the quintillions?

9*10,293,847,561,029,384,756=92,644,628,049,264,46 2,804.
9+2+6+4+4+6+2+8+0+4+9+2+6+4+4+6+2+8+0+4=90.
9+0=9.
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Asim Khan
02-12-2011, 05:20 AM
As-Salam-o-aliekum,

Jazak Allah khair sister for starting this thread.

Alhumdulillah, I am happy to be posting. I post so seldom -- the sister and brother Guestfellow from this thread, and brother Hamza81 and brother zakirs (off the top of my head) are the few members I remember more vividly.

In my last two or three semesters at IIT I could relate to the old and humbled John Nash (A Beautiful Mind), though maybe minus the humbleness. :) My math grades started to go down; a doctor friend of my father's said I was suffering burnout.

Alhumdulillah, I told one of my friends about my favorite scene from the movie where Nash is asked to come into the faculty dinning area to discuss his suitability to receive the Nobel Prize, and he says in a meek manner (IIRC, saw it many years back): "Oh I don't go in there, I just take my sandwich over.. over to the library."

Alhumdulillah, sister Anybody (from Sunniforum.com) wrote a terrific logical argument giving a reason why heaven and hell are a must. The thread starter, Stickyfingers questioned, that how could God punsih some people forever. I have quoted brother Zahed's answer below, but I said I would try and write concerning infinity, to help show the enormity of Major shirk.

I wrote a heuristic exposition for infinity * infinity = infinity some years back. However, I had a different, more mathematical exposition for working with large numbers planned for that thread. The two problems are in the posts below. Feel free to ask any questions. Inshallah, I can give examples to show the principles involved.

Brother Zahed:

Assalaamu 'Alaykum Wa Rahmatullah.
Brother,
There is a verse in the Quran, Tafseer of which is like this (I'm writing it from my memory)- One day some Jews came to Rasulullah S.A.W and asked, in this world we get a limited life and so our sin is confined to this lifetime. But you say that, the Kafir will live in the Jahannam forever. Why we won't live in the Jahannam for the time equal to this life and then get relief? They also showed same logic for Muslims and Jannah. Allah S.W.T answered by that verse that, if they would live in the world forever, they would continue their sinful activities forever. Hence due to their Niyyat, they will live in Jahannam forever.
[...]
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Asim Khan
02-12-2011, 05:25 AM
Sister Anybody: [...] there were parts of Stickyfingers’s post that I wanted to clarify so that others may understand, which I decided to write. [...]

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Asim Khan
02-12-2011, 05:48 AM
Other post below included to show how the opportunity came about:

slartibartfast:
:)

If I recall correctly, the downfall of greek society was due to Hippasus' heresy of proving that applying pythogorus' theorum to a 1x1 right-angle triangle results in an impossible number... sorry, "irrational number" [...] [/slartibartfast]

In the mood to "see" why for some large numbers x^2 = x? [...]

This isn't a proof, just a "show that", but one I think is slick. The main obstacle is showing x+1 = x. We can count the number of atoms in the universe:

1 mole -> 10^27[*]
1 star -> 10^33 kg of H atoms -> 10^(33+3+27) = 10^63 atoms
1 obserable universe [several years old data] -> 10^12 galaxys -> 10^(12+12) stars -> 10^87 atoms
(let) 1 islandthing = 10^13 obserable universes -> 10^100 = 1 googol atoms

Does it make any difference if we add 1 more atom to an island-thing? If we assert that 1+googol = googol then the rest follows as a proof.

I have little choice now but to [do a cheap trick]. 1 followed by as many zeros as the number of atoms in an islandthing = 10^ (10^100) = googolplex. I will, however, stay a bit more physical by considering the number of subsets of an islandthing (taking every atom to be unique).

Observe the correspondence between the subsets of {a,b,c} and three bit binary numbers, where each bit represents the inclusion/exclusion of a particular member:

000 {}
001 {c}
010 {b}
011 {b,c}
100 {a}
101 {a,c}
110 {a,b}
111 {a,b,c}

When we include 0, an n bit number enumerates 2^n numbers (a 3 bit number enumerated 8 numbers above), so the number of subsets of an n element set is 2^n. The number of subsets of an islandthang is 2^googol.

See what happens when we double 2^googol:
2^googol * 2 = 2^(googol+1)
We get more abstract when we consider 2^ (2^googol). Let's multiply this number by itself:

2^ (2^googol) * 2^ (2^googol) = 2^ (2^googol + 2^googol) = 2^ (2^(googol+1))


* edit: whoops, one mole is 6.022 x 10^23 ~= 10^24, don't know why I included another factor of 1,000
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Aprender
02-12-2011, 05:50 AM
I love this thread. Wonderful idea. One of my favorite types of math is trigonometry.
Math is not my strong point but I do thoroughly enjoy it.
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Cabdullahi
02-12-2011, 11:02 AM
Network address : 192.168.1.0 / 25


Laboratory 1 needs 60 hosts




Subnet mask table
/20 255.255.240.0 4096
/21 255.255.248.0 2048
/22 255.255.252.0 1024
/23 255.255.254.0 512
/24 255.255.255.0 256
/25 255.255.255.128 128
/26 255.255.255.192 64 < lab 1
/27 255.255.255.224 32
/28 255.255.255.240 16
/29 255.255.255.248 8
/30 255.255.255.252 4

Lab 1

192.168.1.0 / 26 < network address
192.168.1.1 <host addresses
192.168.1.2
192.168.1.3
192.168.1.4
192.168.1.5
.
.
.
.
.
192.168.1.63 Broadcast address
192.168.1.64 Network address



so computer A in laboratory 1 can be given 192.168.1.1.....
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