Author Topic: Testirajmo Ghoulovo znanje matematike!  (Read 132846 times)

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mac

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Re: Testirajmo Ghoulovo znanje matematike!
« Reply #900 on: 21-04-2019, 23:25:56 »
Mda, lako je sad kad su događaji nezavisni, jer se karte vuku iz različitih špilova. Videću te kod povezanih događaja, recimo karte iz istog špila.

Truman

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Re: Testirajmo Ghoulovo znanje matematike!
« Reply #901 on: 21-04-2019, 23:49:01 »
Било је до сада пар задата и са тим. Само умањим број карата у другом извлачењу у разломку, уместо 52, 51. Ал могуће да тежи задаци тек предстоје!
There is neither creation nor destruction, neither destiny nor free will, neither path nor achievement. This is the final truth.
Sri Ramana

Truman

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Re: Testirajmo Ghoulovo znanje matematike!
« Reply #902 on: 22-04-2019, 02:11:04 »
Мек, опет сам забаговао. Један проблем никако да решим.
You pick three balls in succession out of a bucket of 3 red balls and 3 green balls. Assume replacement after picking out each ball. What is the probability of each of the following events?
Any sequence with 2 reds and 1 green. Answer in reduced fraction form - eg 1/5 instead of 2/10.
Не, одговор није 1/8.
There is neither creation nor destruction, neither destiny nor free will, neither path nor achievement. This is the final truth.
Sri Ramana

Biki

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Re: Testirajmo Ghoulovo znanje matematike!
« Reply #903 on: 22-04-2019, 03:10:37 »
1/6


mac

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Re: Testirajmo Ghoulovo znanje matematike!
« Reply #904 on: 22-04-2019, 09:19:01 »
Ovo "assume replacement" interpretiram kao da loptu vraćamo u korpu kad je odaberemo, i svaki izbor ima iste verovatnoće kao i svaki prethodni. Biranje jedne lopte ima dva ishoda, a pošto je sve nezavisno biranje tri ima osam, pa svaki pojedinačni ishod ima verovatnoću 1/8. Od tih osam ishoda tri imaju dve crvene i jednu zelenu, pa je verovatnoća 3/8.

Truman

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Re: Testirajmo Ghoulovo znanje matematike!
« Reply #905 on: 22-04-2019, 12:52:06 »
мек, кад ти објашњаваш то изгледа тако просто!!
There is neither creation nor destruction, neither destiny nor free will, neither path nor achievement. This is the final truth.
Sri Ramana

Truman

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Re: Testirajmo Ghoulovo znanje matematike!
« Reply #906 on: 07-05-2019, 00:27:32 »
Мек, опет ми је потребан твој бриљантан ум

Let's say Alvin will catch the flu with probability of 1/10 during any given month. Let's also assume that Alvin can catch the flu only once per month, and that if he has caught the flu, the flu virus will die by the end of the month. What is the probability of the following events?
He catches the flu exactly once in the three months from September through November.
There is neither creation nor destruction, neither destiny nor free will, neither path nor achievement. This is the final truth.
Sri Ramana

mac

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Re: Testirajmo Ghoulovo znanje matematike!
« Reply #907 on: 07-05-2019, 10:36:54 »
Pošto je nazebavanje nezavisno svakog meseca onda možemo da gledamo samo tri tražena meseca, a ignorišemo bilo šta što se dešavalo ranije. Postoji osam elementarnih ishoda (dobio ili nije dobio grip svakog od tri meseca, 2^3=8), ali ovi ishodi nemaju istu verovatnoću. Svaki ishod je rezultat tri nezavisna događaja, pa je verovatnoća bilo kog ishoda jednaka proizvodu verovatnoća odgovarajuća tri događaja. Nama su interesantna tri od ovih osam ishoda (slučajevi 100, 010, 001, ako me razumeš).

Neka je P(m) verovatnoća da Alvin dobije grip u mesecu m∈[1,12]. Za svako m verovatnoća je P(m)=1/10, a verovatnoća da se ne desi P(m) je 1-P(m)=9/10. Verovatnoća bilo kog od tri interesantna ishoda je P*(1-P)*(1-P)=81/1000 (verovatnoća da jednog meseca dobije grip, ali da ga u druga tri meseca ne dobije). Verovatnoća da se desi bilo koji od ova tri ishoda je njihov zbir, 243/1000.

Truman

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Re: Testirajmo Ghoulovo znanje matematike!
« Reply #908 on: 07-05-2019, 13:08:13 »
мек, хвала. Ја сам стигао до 81/1000 и ту стао. А у ствари треба сабрати вероватноће за сва три случаја. кад ти објасниш то делује тако просто ( мада ово сам ти већ написао ).
There is neither creation nor destruction, neither destiny nor free will, neither path nor achievement. This is the final truth.
Sri Ramana



Truman

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Re: Testirajmo Ghoulovo znanje matematike!
« Reply #911 on: 14-09-2019, 14:52:18 »
Two Mathematicians Just Solved a Decades-Old Math Riddle — and Possibly the Meaning of Life
Није да ће ово баш да открије смисао живота, али је макар забавно.
There is neither creation nor destruction, neither destiny nor free will, neither path nor achievement. This is the final truth.
Sri Ramana

Meho Krljic

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Re: Testirajmo Ghoulovo znanje matematike!
« Reply #912 on: 15-09-2019, 05:16:10 »
Dobro, to je aluzija na Daglasa Adamsa, jelte  :lol:



Meho Krljic

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Re: Testirajmo Ghoulovo znanje matematike!
« Reply #915 on: 15-12-2019, 06:49:48 »
Mathematician Proves Huge Result on ‘Dangerous’ Problem 
 
Quote

The Collatz conjecture is quite possibly the simplest unsolved problem in mathematics — which is exactly what makes it so treacherously alluring.
“This is a really dangerous problem. People become obsessed with it and it really is impossible,” said Jeffrey Lagarias, a mathematician at the University of Michigan and an expert on the Collatz conjecture.
 
 
(...)
 
 
Lothar Collatz likely posed the eponymous conjecture in the 1930s. The problem sounds like a party trick. Pick a number, any number. If it’s odd, multiply it by 3 and add 1. If it’s even, divide it by 2. Now you have a new number. Apply the same rules to the new number. The conjecture is about what happens as you keep repeating the process.
Intuition might suggest that the number you start with affects the number you end up with. Maybe some numbers eventually spiral all the way down to 1. Maybe others go marching off to infinity.
But Collatz predicted that’s not the case. He conjectured that if you start with a positive whole number and run this process long enough, all starting values will lead to 1. And once you hit 1, the rules of the Collatz conjecture confine you to a loop: 1, 4, 2, 1, 4, 2, 1, on and on forever.
Over the years, many problem solvers have been drawn to the beguiling simplicity of the Collatz conjecture, or the “3x + 1 problem,” as it’s also known. Mathematicians have tested quintillions of examples (that’s 18 zeros) without finding a single exception to Collatz’s prediction. You can even try a few examples yourself with any of the many “Collatz calculators” online. The internet is awash in unfounded amateur proofs that claim to have resolved the problem one way or the other.