Math Is Fun Forum
  Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °

You are not logged in.

#51 2013-03-27 00:38:51

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 86,705

Re: Another coin problem

The sun sign is the position of the sun at birth. The rising sign is calculated from the hour. At least as far as I know.


In mathematics, you don't understand things. You just get used to them.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.

Offline

#52 2013-03-27 00:40:08

Agnishom
Real Member
From: The Complex Plane
Registered: 2011-01-29
Posts: 16,836
Website

Re: Another coin problem

Okay maybe its the rising sign then..,


'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
'Humanity is still kept intact. It remains within.' -Alokananda

Offline

#53 2013-03-27 00:41:29

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 86,705

Re: Another coin problem

The 24 hours are divided into 2 hour periods and your rising sign is computed from there.


In mathematics, you don't understand things. You just get used to them.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.

Offline

#54 2013-03-27 00:45:30

ShivamS
Member
Registered: 2011-02-07
Posts: 3,533

Re: Another coin problem

Speaking of, my prof. recently asked us to search up a proof for the Linearity of Expectation function which I just found.

Offline

#55 2013-03-27 00:58:06

Agnishom
Real Member
From: The Complex Plane
Registered: 2011-01-29
Posts: 16,836
Website

Re: Another coin problem

I would like to see that.


'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
'Humanity is still kept intact. It remains within.' -Alokananda

Offline

#56 2013-03-27 00:58:10

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 86,705

Re: Another coin problem

The linearity of expectation is surprising because there is no need for independence.


In mathematics, you don't understand things. You just get used to them.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.

Offline

#57 2013-03-27 01:01:14

ShivamS
Member
Registered: 2011-02-07
Posts: 3,533

Re: Another coin problem

http://www.proofwiki.org/wiki/Linearity_of_Expectation_Function
Had been searching in textbooks for 6 days-then opened google.

Offline

#58 2013-03-27 01:05:44

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 86,705

Re: Another coin problem

2 problems:

The 52 cards are spread out in a line what is the expected number of adjacent cards of the same suit.

The 52 cards are spread out in a line what is the probability that adjacent cards are of the same suit.

One is hard and one is easy because of linearity.


In mathematics, you don't understand things. You just get used to them.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.

Offline

#59 2013-03-27 01:10:08

Agnishom
Real Member
From: The Complex Plane
Registered: 2011-01-29
Posts: 16,836
Website

Re: Another coin problem

Is the answer of the first 0.25*0.25*51??


'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
'Humanity is still kept intact. It remains within.' -Alokananda

Offline

#60 2013-03-27 01:15:34

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 86,705

Re: Another coin problem

Hi;

I am not getting that.


In mathematics, you don't understand things. You just get used to them.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.

Offline

#61 2013-03-27 01:31:00

Agnishom
Real Member
From: The Complex Plane
Registered: 2011-01-29
Posts: 16,836
Website

Re: Another coin problem

Why? Whats wrong?


'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
'Humanity is still kept intact. It remains within.' -Alokananda

Offline

#62 2013-03-27 01:32:45

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 86,705

Re: Another coin problem

The probability that the second card is the same suit given the first is 12 / 51.


In mathematics, you don't understand things. You just get used to them.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.

Offline

#63 2013-03-27 02:17:07

anonimnystefy
Real Member
From: The Foundation
Registered: 2011-05-23
Posts: 15,525

Re: Another coin problem

I would say the answer to the first one is 12.


“Here lies the reader who will never open this book. He is forever dead.

“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

Online

#64 2013-03-27 02:19:30

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 86,705

Re: Another coin problem

That is what I am getting too. Of course it is a bad answer!


In mathematics, you don't understand things. You just get used to them.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.

Offline

#65 2013-03-27 02:21:54

anonimnystefy
Real Member
From: The Foundation
Registered: 2011-05-23
Posts: 15,525

Re: Another coin problem

Actually, shouldn't it be 11?


“Here lies the reader who will never open this book. He is forever dead.

“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

Online

#66 2013-03-27 02:26:42

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 86,705

Re: Another coin problem

Why do you think so?


In mathematics, you don't understand things. You just get used to them.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.

Offline

#67 2013-03-27 02:33:29

anonimnystefy
Real Member
From: The Foundation
Registered: 2011-05-23
Posts: 15,525

Re: Another coin problem

No, sorry. I forgot there were 13 cards in a suit.

Why is the answer of 12 wrong then?


“Here lies the reader who will never open this book. He is forever dead.

“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

Online

#68 2013-03-27 02:37:26

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 86,705

Re: Another coin problem

I did not say it is wrong. It is correct but it is still a bad answer. Sufficient for the people on forums but not sufficient for real work!


In mathematics, you don't understand things. You just get used to them.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.

Offline

#69 2013-03-27 02:48:54

anonimnystefy
Real Member
From: The Foundation
Registered: 2011-05-23
Posts: 15,525

Re: Another coin problem

Why not?


“Here lies the reader who will never open this book. He is forever dead.

“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

Online

#70 2013-03-27 02:56:09

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 86,705

Re: Another coin problem

Ever seen the way these guys work? Ever checked any of their answers? Conjectures that they never even try a single example against...

Numerical work demands 2 solutions for every problem! Combinatorics and probability should be treated with the same respect.


In mathematics, you don't understand things. You just get used to them.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.

Offline

#71 2013-03-27 02:58:23

anonimnystefy
Real Member
From: The Foundation
Registered: 2011-05-23
Posts: 15,525

Re: Another coin problem

Uh-huh. Ok, then we can also use a simulation to confirm the answer.


“Here lies the reader who will never open this book. He is forever dead.

“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

Online

#72 2013-03-27 03:00:14

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 86,705

Re: Another coin problem

Already did that, got 12.0004. Now I can hand the answer into my boss and get paid the big bucks.


In mathematics, you don't understand things. You just get used to them.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.

Offline

#73 2013-03-27 03:13:37

anonimnystefy
Real Member
From: The Foundation
Registered: 2011-05-23
Posts: 15,525

Re: Another coin problem

You work in a casino?


“Here lies the reader who will never open this book. He is forever dead.

“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

Online

#74 2013-03-27 03:17:12

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 86,705

Re: Another coin problem

Several of them in the past.


In mathematics, you don't understand things. You just get used to them.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.

Offline

#75 2013-03-27 03:48:19

Agnishom
Real Member
From: The Complex Plane
Registered: 2011-01-29
Posts: 16,836
Website

Re: Another coin problem

(12/51)*51 = 12

Did you state that the cards were all from the same deck?

What is the answer to the other problem?

Last edited by Agnishom (2013-03-27 03:49:05)


'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
'Humanity is still kept intact. It remains within.' -Alokananda

Offline

Board footer

Powered by FluxBB