Math Trick

[DRChicago]

"Perhaps not my place to be answering for erynthered, but we ride each other pretty hard around here in good natured fun."

 

Yep I agree -- that's why I've been a registered member since June of 2002

 

"After 23 posts you may not have figured that out, but considering that most of the folks on this board are short 1, maybe 2 brain cells (but all pretty damned big on heart), I think you need to turn down your "take it personal" meter."

 

BTW I've only posted 23 times but have been a registered member 14 months longer than you so I don't need a lecture on the nature of the board. I most often post when people are bantering in my areas of academic expertise (Theology and Film post production) or when people take it out on the little guys. Nothing personal just sticking up for the little guy.

 

If Red had been self effacing (including himself as one short on brain cells) the tone is entirely different.

 

On the "life is behind the chair" comment - that's one reason why I have only 23 posts though I check in alomost every day.

 

Peace?

[McGill Bill]

the logic in this is inherently flawed...every 0 term in the original is matched by a 1-1 term, so for arguements sake, take the first 2 terms...

 

0=0+0

0=1-1+1-1

factor it out you get

0=1-(1-1)-1

and 0=0

 

no matter how many (1-1) terms there are, you are always going to have that last -1 term chillin out there by himself, waiting to cancel your 1st 1 term...

343372[/snapback]

 

You've got it mostly right, but the problem is that it IS an infinite series, meaning that it never ends, so you can't have a (-1) at the end. The real answer is that (1 - 1 + 1 - 1 + ...) does not equal zero. It's a divergent series, meaning it doesn't have a sum, so the real flaw is in the second line. But close enough

[respk]

"lighten up Francis"

[Ramius]

You've got it mostly right, but the problem is that it IS an infinite series, meaning that it never ends, so you can't have a (-1) at the end. The real answer is that (1 - 1 + 1 - 1 + ...) does not equal zero. It's a divergent series, meaning it doesn't have a sum, so the real flaw is in the second line. But close enough

343394[/snapback]

 

ah, yes divergent series...thats the idea i was getting at, but couldnt think of the correct wording...its been about 4-5 years since i have done any real math or logic, thats why it escaped me...the trick is still pretty cool tho

[BuckeyeBill]

Here's a mindteasing story.

 

After a Bills game, you and your two buddies want to get a hotel room... the price of this particular room is

 

30 bucks.... easy, each of you chip in 10 dollars and go to your room.

 

Well, the hotel manager checks and notices a special... the room should only be 26 dollars and not 30. So, the manager gives four bucks to the bellboy to give to you and your two buddies.

 

The bell boy figures out, there are only three of them, so I will keep one myself. He gives back one dollar to each of you and leave with one still in his pocket.

 

So how much did the room cost?

 

Well each of you only ended up paying 9... after you got the dollar back so...

 

9X3=27 dollars... plus the 1 dollar that the Bellboy has equals 28 bucks.

 

Where did the other two dollars go?

[Crap Throwing Monkey]

You're dividing by (A-B) on both sides at one point. You can't do that, because A-B=0, and you're essentially saying that 2 times infinity equals 1 times infinity.

 

How about this one:

 

0 = 0 + 0 + 0 + 0 + 0 + ...

0 = 1 - 1 + 1 - 1 + 1 - 1 + 1 - ...

0 = 1 - (1 - 1) - (1 - 1) - (1 - 1) - ...

0 = 1

343342[/snapback]

 

You can divide by zero, but only in the manner of f(x)/y in the limit of y going to 0. Ergo, if you're dividing y/y in that limit, you reach the conclusion that 0/0 = 1.

 

And technically, 2 times infinity does equal one times infinity. The only mathematical operation you can perform on infinity is raising it to the power of infinity...which gives you a different "kind" of infinity.

[Crap Throwing Monkey]

Why does A+B=B?

343333[/snapback]

 

Because (A+B)(A-B) = A^2 - B^2, and since A^2 = AB, A^2 - B^2 = AB-BB = B(A-B). Ergo, A+B = B.

[McGill Bill]

The flaw is when you say each guest only spent 9 dollars. They actually spent 10, and got one back from the hotel. There's a difference. In the way you added up, you forgot to account for the fact that those three dollars still exist as part of the original 30, it's just that they lie in the hotel guests' hands. However, that totals 31. The truth is, you have to SUBTRACT one for the bell boy taking it, not add. It has been totally removed from the hotel-guest transaction, leaving you with the original 30 dollars.

[Ramius]

Here's a mindteasing story.

 

After a Bills game, you and your two buddies want to get a hotel room... the price of this particular room is

 

30 bucks.... easy, each of you chip in 10 dollars and go to your room.

 

Well, the hotel manager checks and notices a special... the room should only be 26 dollars and not 30.  So, the manager gives four bucks to the bellboy to give to you and your two buddies. 

 

The bell boy figures out, there are only three of them, so I will keep one myself.  He gives back one dollar to each of you and leave with one still in his pocket.

 

So how much did the room cost?

 

Well each of you only ended up paying 9... after you got the dollar back so...

 

9X3=27 dollars... plus the 1 dollar that the Bellboy has equals 28 bucks.

 

Where did the other two dollars go?

343410[/snapback]

 

 

The flaw is when you say each guest only spent 9 dollars. They actually spent 10, and got one back from the hotel. There's a difference. In the way you added up, you forgot to account for the fact that those three dollars still exist as part of the original 30, it's just that they lie in the hotel guests' hands. However, that totals 31. The truth is, you have to SUBTRACT one for the bell boy taking it, not add. It has been totally removed from the hotel-guest transaction, leaving you with the original 30 dollars.

343422[/snapback]

 

yup, exactly right, mcgill...another way to look at it is this...the room cost $26, you each pay 9, so 9x3 = 27, minus the $1 the bell boy took = $26, the cost of the room...all in the wording...

[crazyDingo]

AMACHURS! YOO'S GUYS R AMACHURS!

 

Amaze your friends at parties with this:

 

Take the year you were born

 

add 180 to it

 

multiply that by the first two numbers of your home address; if you live in an apartment, use the first 3 numbers of your unit #, unless you live in a one or two numbered unit (like unit 12) then you should use the first 3 digits of your telephone number

 

divide that by 3.14

 

add the year you graduated; if you didnt graduate college, use the year you graduated high school; if you never graduated use the year you were first incarcerated

 

multiply by 1.618

 

convert your first name into a number by using the a=1, b=2, c=3 method and add this to the original number

 

multiply by 0

 

 

 

IT EQUALS ZERO! IS THAT CRAZY OR WHAT? I love that trick.

[IBTG81]

I have a headache!

 

[Crap Throwing Monkey]

I have a headache! 

 

 

343546[/snapback]

 

If you multiply it by 0, it'll go away...

If, on the other hand, you add 2 to it, multiply it by 300, divide it by 10, subtract 30, multiply it by 2, subtract 60, and then divide by 60, you'll still have it.

[McGill Bill]

You can divide by zero, but only in the manner of f(x)/y in the limit of y going to 0.  Ergo, if you're dividing y/y in that limit, you reach the conclusion that 0/0 = 1. 

 

And technically, 2 times infinity does equal one times infinity.  The only mathematical operation you can perform on infinity is raising it to the power of infinity...which gives you a different "kind" of infinity.

343412[/snapback]

 

But you're not dividing y by y. You're dividing B and 2B, which presumably are real, non-zero numbers by y as y approaches zero if you'd rather look at it as a limit. This limit (the limit as y approaches 0 of B/y) is infinity, not 1.

[Ramius]

But you're not dividing y by y. You're dividing B and 2B, which presumably are real, non-zero numbers by y as y approaches zero if you'd rather look at it as a limit. This limit (the limit as y approaches 0 of B/y) is infinity, not 1.

343668[/snapback]

 

what do you do for a living bill? You are fairly well versed in math...i used to know quite a bit (i was a math major for a brief time in school, but eventually got sick of the proofs and abstract stuff, and settled on the math minor), but you seem to have got your sh-- together...

[Crap Throwing Monkey]

But you're not dividing y by y. You're dividing B and 2B, which presumably are real, non-zero numbers by y as y approaches zero if you'd rather look at it as a limit. This limit (the limit as y approaches 0 of B/y) is infinity, not 1.

343668[/snapback]

 

Actually, the limit as B -> 0 of B/2B is half of B/B as B -> 0...is 1/2. It doesn't diverge to infinity because, to put it colloquially, the B's cancel. The cancellation of terms between numerator and denominator doesn't suddenly stop at 0.

 

Or if you want to get fancy, take the derivitave of x/x with respect to x: (d/dx)(x/x) = 1/x - (x/x^2) = 1/x - 1/x = 0. That says the slope of the curve is zero - it's flat. Which means evaluating the equation (x/x) at any point a gives you the same value as at any point b...ergo, if b is non-zero, b/b is 1, and a/a = b/b = 1 even if a is zero. QED.

 

And that's no "subtract the current time from twice the current time, and you get the current time!" mathematical trick. That's straightforward Calc 101.

[McGill Bill]

Actually, the limit as B -> 0 of B/2B is half of B/B as B -> 0...is 1/2.  It doesn't diverge to infinity because, to put it colloquially, the B's cancel.  The cancellation of terms between numerator and denominator doesn't suddenly stop at 0. 

 

Or if you want to get fancy, take the derivitave of x/x with respect to x: (d/dx)(x/x) = 1/x - (x/x^2) = 1/x - 1/x = 0.  That says the slope of the curve is zero - it's flat.  Which means evaluating the equation (x/x) at any point a gives you the same value as at any point b...ergo, if b is non-zero, b/b is 1, and a/a = b/b = 1 even if a is zero.  QED. 

 

And that's no "subtract the current time from twice the current time, and you get the current time!" mathematical trick.  That's straightforward Calc 101.

343693[/snapback]

 

Wow CTM, I have to say that your online name suits you well

[Crap Throwing Monkey]

Wow CTM, I have to say that your online name suits you well

343697[/snapback]

 

Hey, the calculus proof is a HARD proof, not just crap. It'll stand up to any criticism you want to throw at it.

 

Degrees in astronomy and physics, m'boy...I'm not the world's greatest mathematician, but I ain't no slouch, either...

[stuckincincy]

Hey, the calculus proof is a HARD proof, not just crap.  It'll stand up to any criticism you want to throw at it. 

 

Degrees in astronomy and physics, m'boy...I'm not the world's greatest mathematician, but I ain't no slouch, either... 

343699[/snapback]

 

Hello, Lazarus.

 

Your pal, stuckincincy.

[/dev/null]

Here is a math trick that  will stump you.

 

 

          1. Grab a calculator. (It will be easier than doing it in your

      head)

          2.  Key in the first three digits of your phone number (NOT the

      area code)

          3. Multiply by 80

          4. Add 1

          5. Multiply by 250

          6. Add the last 4 digits of your phone number

          7. Add the last 4 digits of your phone number again.

          8. Subtract 250

          9. Divide number by 2

 

          Do you recognize the answer?

343254[/snapback]

 

1) don't need a calculator if you know algebra

2) x

3) 80x

4) 80x + 1

5) 20000x + 250

6) 20000x + 250 + y

7) 20000x + 250 + 2y

8) 20000x + 2y

9) 10000x + y

 

so what you're saying is if my number was 555-1234, the answer to this childish math problem would be 5551234

 

where's the sarcasm button?

 

[/dev/null]

You're dividing by (A-B) on both sides at one point. You can't do that, because A-B=0, and you're essentially saying that 2 times infinity equals 1 times infinity.

 

How about this one:

 

0 = 0 + 0 + 0 + 0 + 0 + ...

0 = 1 - 1 + 1 - 1 + 1 - 1 + 1 - ...

0 = 1 - (1 - 1) - (1 - 1) - (1 - 1) - ...

0 = 1

343342[/snapback]

 

sounds like the end of the movie Clue when they're trying to figure out how many shots were fired