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#42576 Re: Jai Ganesh's Puzzles » Problems and Solutions » 2005-08-29 20:03:52
Solution to problem#k+3 : kylekatarn is correct.
Problem # k+5
Use each digit 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9 exactly once to form two five-digit numbers that when multiplied produce the largest quantity.
#42577 Re: Introductions » Winter Lover » 2005-08-29 16:07:01
Welcome to the forum, John!
Your posts and replies are interesting, keep posting 
#42578 Re: Help Me ! » Intergration Rock Solid!!! Please Help Asap.. » 2005-08-28 20:09:03
Flowers4Carlos, tahnk you for solving the problem.
The steps are easy to understand. Keep up the good work!
#42579 Re: Jokes » Mathematics jokes » 2005-08-28 16:11:55
Thanks Rora, we miss you in this forum!
#42580 Re: Introductions » hiii... » 2005-08-28 16:10:53
Sometimes, it is spelt Djakarta!
#42581 Re: This is Cool » I'm cracking up » 2005-08-27 17:44:06
Mikau, Ahgua.....I am sorry, yesterday, when I was
trying to copy the diagram, I saw two same posts
(maybe, I thought I saw) of the diagram, to simplify,
I tried to delete one, and the entire post and got deleted.
I shall be much much more careful in the future,
and thanks for posting it before I requested you!
Nice question, brilliant reasoning.
#42582 Jokes » Mathematics jokes » 2005-08-26 19:09:21
- Jai Ganesh
- Replies: 279
How do you prove in three steps that a sheet of paper is a lazy dog?
1. A sheet of paper is an ink-lined plane.
2. An inclined plane is a slope up.
3. A slow pup is a lazy dog.
Mathematics is made of 50 percent formulas, 50 percent proofs, and 50 percent imagination.
A tragedy of mathematics is a beautiful conjecture ruined by an ugly fact.
Philosophy is a game with objectives and no rules.
Mathematics is a game with rules and no objectives.
How many mathematical logicians does it take to replace a lightbulb?
None: They can't do it, but they can prove that it can be done.
#42583 Re: Jai Ganesh's Puzzles » Problems and Solutions » 2005-08-26 18:39:59
Problem #k+4
A polyhedron has 12 faces(sides) and 18 edges. How many vertices does it have?
#42584 Re: Guestbook » cool stuff » 2005-08-26 18:25:16
Computer games, Internet, Coke, Beaches...
#42585 Re: Help Me ! » Hep with Trig. please :) » 2005-08-26 00:09:31
cosecA + cotA = 3
To find cosecA - cotA,
one should remember,
cosec²A - cot²A = 1
From this, we get
(cosecA+ cotA)(cosecA - cotA)=1
Given cosecA + cotA = 3,
3(cosecA-cotA)=1
cosecA-cotA=1/3
cosecA + cotA + cosecA-cotA = 3+1/3 = 4/3
2cosecA = 4/3
cosecA=2/3
sinA=3/2 funny
#42586 Re: Help Me ! » Variations » 2005-08-25 23:59:17
Lets assume the job can be completed by 5 men in 'x' days.
Therefore, the number of mandays required is 5x.
If one more man is hired, the total number of men = 6 and the number of days required = x-8. Therefore, the total number of mandays = 6(x-8)
Equating the two,
5x = 6(x-8)
5x = 6x - 48
-x = -48 or x = 48.
Therefore, the number of mandays required for the work is 5x48 = 240.
If y men moreare employed for completion of the work in 28 days earlier,
number of men = 5+y, number of days = 48-28=20,
the number of mandays = (5+y)20
but, we already know that the number of mandays required for the work is 240,
therefore,
(5+y)20=240, 5+y=240/20 => 5+y=12, y=7
Therefore, 7 more men would be required.
#42587 Re: Jai Ganesh's Puzzles » Problems and Solutions » 2005-08-25 20:26:53
Problem #k+3
A cube of dimensions 10cm x 10cm x 10cm is made up of smaller cubes of dimensions 1cm x 1cm x 1cm. If the outermost layer of smaller cubes are taken off, how many smaller cubes would be left?
#42588 Re: Puzzles and Games » What next? » 2005-08-25 16:15:58
A, T, G, C..next comes L
Aries, Taurus, Gemini, Cancer,..Leo.
#42589 Re: Puzzles and Games » What next? » 2005-08-24 21:38:23
I expected this would happen....... 
A, T, G, C are NOT
Adenine, Thymine, Guanine and Cytosine.
#42590 Puzzles and Games » What next? » 2005-08-24 20:57:48
- Jai Ganesh
- Replies: 7
What comes next in the series?
A, T, G, C, _
#42591 Re: Jai Ganesh's Puzzles » Problems and Solutions » 2005-08-24 16:34:02
Problem #k+2
I have a certain number of eggs in my store.
If you divide the number of eggs by 2 there will be one egg left.
If you divide the number of eggs by 3 there will be two eggs left.
If you divide the number of eggs by 4 there will be three eggs left.
If you divide the number of eggs by 5 there will be four eggs left.
If you divide the number of eggs by 6 there will be five eggs left.
If you divide the number of eggs by 7 there will be six eggs left.
If you divide the number of eggs by 8 there will be seven eggs left.
If you divide the number of eggs by 9 there will be eight eggs left.
If you divide the number of eggs by 10 there will be nine eggs left.
If you divide the Number of eggs by 11 there will be NO EGGS left!
What is the minimum number of eggs I can have in my store?
#42592 Re: Help Me ! » Hep with Trig. please :) » 2005-08-24 00:16:35
You are right!
When x=0,
2sinx.cosx + cos^2x = 1
But how do we get a solution x=0?
2sinx.cosx + cos^2x = 1
sin2x + cos^2x = 1,
sin2x = 1-cos^2x
sin2x = sin^2x
this would be true only when x=0
But is there any (other)mathematical way it can be shown that x=0 is a solution?
#42593 Re: Dark Discussions at Cafe Infinity » Wink Murder 3 » 2005-08-23 21:14:05
Good wishes to all awaiting GCSE results
#42594 Re: Help Me ! » Integration. Where is the 2 coming from? » 2005-08-23 21:12:52
∫udu = u²/2 + c
∫u is not defined.
In integration, the dx or du component is important.
∫1/x is not defined. But, ∫(1/x)dx = logx + c or lnx + c(as denoted in some textbooks).
Similarly, ∫(x^n)dx = [(x^n+1)/(n+1)] + c.
#42595 Re: Jai Ganesh's Puzzles » Problems and Solutions » 2005-08-23 21:04:41
Problem #k+1
In a University, a student has to take necessarily Physics, Chemistry or Mathematics. The students are permitted take any two of them or even all the three of them. If 85 students take Physics, 65 students take Chemistry, 100 students take mathematics, 30 students take both Physics and Chemistry, 40 students take both Physics and Mathematics and none of the students take Chemistry and Mathematics or all three of them, how many students are there in the University?
#42596 Re: This is Cool » A Pi Fundraiser » 2005-08-23 16:24:34
Nice T Shirt, Good cause!
I hope they get more funds than what they expect!
#42597 Re: Dark Discussions at Cafe Infinity » Wink Murder 3 » 2005-08-23 00:24:30
Thats right, my post saying I'm in the game is gone!
Anyhow, once again, I am playing
#42598 Re: Jai Ganesh's Puzzles » Problems and Solutions » 2005-08-22 16:25:14
Problem #k
What is the total number of squares, of all sizes, in a Chess board?
#42599 Re: Help Me ! » money in bags question someone asked » 2005-08-22 16:23:29
Yes, seven bags is right, but I would have put the Dollars in the bags this way:-
1, 2, 4, 8, 16, 32 and 8.
Your solution is correct too!
#42600 Re: Jai Ganesh's Puzzles » Problems and Solutions » 2005-08-17 16:29:10
Problem # n+11
A circle of diameter 'a' is cut from a square metal sheet of side 'a'. From the four corner cuttings, four circles are cut. Whats the maximum area of the four circles put together?