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#43576 Re: This is Cool » the philosophy and science behind teleportation » 2005-07-31 18:55:51

Mathematics lovers discusing Futurology and Genetics (and Cybernetics?) roll

#43577 Re: Jai Ganesh's Puzzles » Problems and Solutions » 2005-07-31 18:54:04

As always, you are corect, Mathsy!
I shall show how I did it.
Assume both candles are 'h' inches in height.
The height of the first candle reduces by h/4 every hour and that of the second reduces by h/3.
Lets assume in time 't' hours, the first is twice the height of the second.
Therefore,
h - t(h/4) = 2 [h - t(h/3)]
h - ht/4 = 2h - 2ht/3
h = 2ht/3 - ht/4
h = 5ht/12
Cancelling h on both sides,
1 = 5t/12
or t = 12/5
The unit we had taken was hours,
therefore, in 12/5 hours, that is 2 2/5 hours, one will be double the height of the other.
Simplified, it is 2 hours and 24 minutes.

#43578 Re: Help Me ! » what u think of this problem » 2005-07-31 18:36:24

MathsIsFun wrote:

Let's plug in some numbers just to get this started:

x=1: 3x^2 + x = 4y^2 +y  becomes 5 =  4y^2 +y

When we put x=1,
3x² + x = 3(1² ) + 1 = 4
Therefore,
4y² + y - 4 = 0
y = [-1 ± √ (1 + 64)]/8 = [-1 ± √ 65 ]/8
which is an irational number.
We see that here too x-y is not the square of a natural number smile

#43579 Re: Help Me ! » what u think of this problem » 2005-07-31 18:21:00

juki wrote:

x and y are two natural numbers such that 3x^2 + x = 4y^2 +y

Put x=2,
we get 4y² + y - 14 = 0, Solving,
we get y = [-1 ± √(1 + 224)] / 8
y = -2 or 1.75
Neither of them are Natural Numbers!
x - y is NOT always a square of a natural number roll

#43580 Re: Jai Ganesh's Puzzles » Problems and Solutions » 2005-07-29 19:54:39

Two candles A and B, of equal height but different circumferences, burn for 4 hours and 3 hours respectively. If the two are lit at the same time, after what time would one candle be half the height of the other? smile

#43581 Re: Help Me ! » Hi » 2005-07-29 18:22:15

Nora can paint 1/6 of a house in 1 day.
Therfore, she takes 6 days to paint the house.
Meera can paint the whole house 2 days faster.
So, she can paint the house in 4 days.
In one day, Meera can paint 1/4 of the house.
If both of them paint the house together, in one day,
they can paint (1/6+1/4) of th house. That is,
10/24 or 5/12. Therefore, the whole house can be painted
by them in 12/5 days, that is 2 2/5 days. smile

#43582 Re: This is Cool » the philosophy and science behind teleportation » 2005-07-28 18:27:54

We are discussing this 2.500 years ahead of mankind roll
Maybe in 4,500 AD, brain and the body could be digitized,
maybe then the DNA pattern would be
010100101011100101011001011100011010100010110001.........................
and not
AGCTGGCTAACGTTACTGTTACACGTACGGAATCAGTTAAGCTAAGCT..........

#43583 Re: Dark Discussions at Cafe Infinity » do fish have a personality » 2005-07-28 16:51:29

thinkdesigns wrote:

i don't think fish have real process of their mind, it is proven that they don't feel pain.

It is wrong to assume fish don't feel pain. Any member of the animal kingdom that reacts to touch does feel pain (I think smile)

#43584 Re: This is Cool » will tehre ever be a single particle that makes EVERYTHING » 2005-07-28 16:36:40

thinkdesigns wrote:

......or will it just keep getting smaller, if we do we will have gotten to the smallest possible thing,.....

Atoms were considered to be the building blocks, then the subatomic particles were discovered....and now, it is said that the subatomic particles like neutrons, protons, electorns etc are made up of quarks;
but I am not sure whether that is true for neutrinos, mesons, muons, positrons etc. roll

#43585 Re: Help Me ! » Relation between: inv, arc, co, arcco?? » 2005-07-28 16:31:30

That is neatly explained.
Both Sin-¹x and Arcsin x are one and the same, and both are in use in Mathematics Textbooks.
To make things simple, if Sin x = 1/2,
it follows that                  Sin -¹(1/2) = x
or                                 ArcSin(1/2)  = x

#43586 Re: Dark Discussions at Cafe Infinity » Serious Discussion! » 2005-07-27 00:09:01

An eye for an eye, a tooth for a tooth....
Extrapolated,
a life for a life roll
It takes the society nowhere.
But what do we do with criminals involved in
Homicide / Terrorism / Drug trafficking / Adultery / Molesting ?
Forgive them?
Award a lesser sentence like life imprisonment??
Banish them ??? roll

#43587 Re: Help Me ! » Integration... » 2005-07-27 00:01:50

GurraTedden wrote:

dx=asin(y)dt

(a is a constant value)

where y=y(t)

∫dx = ∫ asinyt dt
∫dx = a ∫sinyt dt

x = a(-cosyt/y) + Constant ??????????? roll

#43588 Re: Guestbook » maths » 2005-07-26 23:03:07

shelly wrote:

what is your name
from shelly

Hi Shelly,
There are 909 registered users in this forum.

#43589 Re: This is Cool » One divided by Infinity » 2005-07-25 20:32:22

The logic seems acceptable.
It is easy to say 1/∞ is 0 because 1/0 is ∞,
just as 1/(a/b) = b/a.
If 1/a=b, it follows that 1/b=a smile
Indeterminate forms are only when both a and b are equal to zero,
or both a and b are equal to infinity.
Abishek, you missed another indeterminate form.
That is 0^0 smile

#43590 Re: Help Me ! » . » 2005-07-25 19:33:58

The binomial expansion of the Left Hand Side
contains two terms, among many, which are
a^a*n and b^a*n which appear to make the LHS greater than the RHS,
but when we assign arbitrary values,
say a=10, b=1,000,000,000 and n=100
the LHS is (1,000,000,010)^1000, which would contain 9,001 digits;
the RHS becomes
100 x (100^1,000,000,000) which would contain more than 2 billion digits!
This happened because we assumed b>>n.
Otherwise, the LHS may be greater.
Say, when a=10, b=100, n=1000.
LHS would be 110^10,000 containing 20,414 digits and the RHS would be much smaller, viz. 100*(1000^100), containing approximately 300 digits! smile

#43591 Re: Help Me ! » As easy as it seems? » 2005-07-25 16:29:36

You may also remember, given the roots of a quadratic equation, the equation can be got thus:-

x² -(Sum of the roots)x + (products of the root) = 0

#43592 Re: Help Me ! » Substitution Method (where two lines cross) » 2005-07-25 16:26:05

Solving the two equations, you get
x = -5/2, y = -1/6
Hence, the two lines cross at
(-5/2, -1/6)

How the two equations are solved:-
First equation can be written as                x+3y = -3
The second equation can be written as     x - 3y = -2
Adding the two, we get                           2x = -5, or x = -5/2
Substituting this value in equation (1)     -5/2 + 3y = -3
                                                                       3y = -3 + 5/2
                                                                       3y = -1/2
                                                                         y = -1/6

#43593 Re: This is Cool » Which of the two is greater? » 2005-07-25 16:20:06

kylekatarn wrote:

it seems that yCritical "slowly"(?) approaches the limit of 1 as x approaches +oo

looking forward to hear comments on this topic!

Yes, you are correct! ycritical approaches 1, but is certainly greater than 1, as x approaches + ∞

#43594 Re: Dark Discussions at Cafe Infinity » Wink Murder 2 » 2005-07-25 16:15:49

I got killed when I was riding a bike, and I was shot at a short range with a pistol in the head sad

#43595 Re: Jokes » Mnemonics » 2005-07-22 22:54:44

Don't ever try to derive a mnemonic for pi.......
That would be a useless exercise.... sad

#43596 Re: Jokes » Mnemonics » 2005-07-22 22:37:48

The world record holder remembers 100,000 places smile

#43597 Introductions » Enough is enough! » 2005-07-22 22:35:41

Jai Ganesh
Replies: 11

Okay, I shall tell you who I am!
I am J Ganesh, who forgot thinking after 15 years of age.....
I think more like the Britons than they do,
I am simply JG or Socrates Ganesh...
and my idol is the greatest mathematician ever....
Niels Henrik Abel....
smile

#43598 Re: Help Me ! » Im beginning to think this is impossible.... » 2005-07-22 22:29:02

Thanks, Mathsisfun,
I am on the verge of post # 200
and this an occassion for me to celebrate,
I shall take a big chunk of thhat big_smile

#43599 Re: This is Cool » Which of the two is greater? » 2005-07-22 22:25:51

Mathsy, I think you missed this post!
With all the available technology, you could have well improved upon those digits! smile

#43600 Jokes » Mnemonics » 2005-07-22 22:17:32

Jai Ganesh
Replies: 14

To
express
e
remember
to
memorize
a
sentence
to
simplify
this.
Can you think of mnemonics for pi?

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