4 = 5?

.5 = -.5, yes it is wrong.

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A wise man once said "A person with half a clue is more dangerous than a person with or without one."

The Micro$haft BSOD T-Shirt

Duh... of course it''s wrong :/. I MEANT assuming that a == b if a^2 == b^2.

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make it absolute

|(4-4.5)| = |(5 - 4.5)|
|-.5| = |.5|


the first line is wrong too

16-36 != 25-15
-20 != 10

the second line doesnt work either

4*4 - 9*4 = 5*4 - 9*5
16 - 36 = 20 - 45
-20 != -25

the third line is ok tho

4*4 - 2(4.5 * 4) = 5*5 - 2(4.5 * 5)
16 - 36 = 25 - 45
-20 = -20

fourth line isnt even close

sqr(4) - 2(4.5 * 4) + sqr(4.5) = sqr(5) - 2(4.5 * 5) + sqr(4.5)
8 - 26 + 20.25 = 25- 45 + 20.25
2.25 != 0.25

fifth line is ok

sqr(4 - 4.5)| = sqr(5 - 4.5)
.25 = .25

line 6 as ive already described above must use absolutes
make it absolute

|(4-4.5)| = |(5 - 4.5)|
.5 = .5



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Whats a pretty girl like you doing in a dirty mind like mine?

Did you mean 16 - 36 = 25 - 45?
Otherwise you are trying to prove two unequal things equal.
I am assuming however, that because you meant 45.

There is nothing wrong with the second step, but it is easier then you are making it.

following your example:

4*4 - 9*4 = 5*5 - 9*5 // factor
4 * (4 - 9) = 5 * ( 5 - 9)
4 * ( 4 - 9) = 5 * (-4)
(4 - 9) = 5 * (-1)
-5 = -5

Or you could just say at the beginning of your eqaulity

16-36 = 25-45

-20 = -20

Just to inform you, another thing that you did wrong was the addition of square roots.

sqr(5) + sqr(4) != sqr(5 + 4)
4.236 != 3.

i think sqr meat Squared not Square Root

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Whats a pretty girl like you doing in a dirty mind like mine?

Yeah, you''re right. It does make more sense as squared then square root. I only read the first two posts so I thought he was trying to do something crazy like take the square roots of both sides. Guess I should read it all before I reply.

2 + 2 = 5 for extremely large values of 2.

quote:

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Original post by abe_bcs
I MEANT assuming that a == b if a^2 == b^2.

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Yes, that assumption is incorrect; easily shown:

if (-1)^2 == (1)^2 then -1 == 1.


You can say that if a^2==b^2, then abs(a)==abs(b).
Or you can say that if a==b, then a^2==b^2.

But the assumption in your derivation was incorrect (ie, the step you marked), which is why you came up with the wrong answer.

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Can anyone spot the fallacy here?

(NB: I use the = sign for equality, not for an assignment operator. I''m not writing in pseudocode.)

1) if x = y, then x - y = 0
2) 2(x - y) = 0
3) 2(x - y) = (x - y)
4) Dividing by the common factor (x - y) yields 2 = 1

Obviously, 2 is not equal to 1 in the normal number system, so there is something wrong with the above reasoning. Try to find it (it''s not hard at all).

Division by zero. (x-y)==0 so when you divide by (x-y) in the last step, everything blows up.

I''ve got a really good one for you:
take 0.9999999... where the nines continue forever, without ever stopping. In normal notation this is 0.9 with a dot above the nine. Then multiply it by ten. You get 9.99999... with the nines continuing on forever, right? Then subtract 0.999999... from it. You get 9, right? Then divide by 9. You get 1.

"So what?" you say, it''s just a trick. But if you take x, multiply by ten to get 10x, subtract x to get 9x and divide by 9, you get x.

Therefore 0.99999999999... == 1. As long as the nines continue forever to infinity, otherwise it doesn''t work.

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Please state the nature of the debugging emergency.

sharewaregames.20m.com

(Disregards pouya''s comment)

If .999999 = 1
then we could subtract .9999999999 from both sides of the equation:

0 = (1 - .999999999)

Then times it by 1 / .999999999999 and I believe we would get:

0 = 1

Is that correct?


(o/t: out of curiosity, how do you pronounce "pouya", is it "poy-ya", "pooh-yah" or "pow-ya" or what?)

Trying is the first step towards failure.

If you can prove that 4 = 5, then you''re a genius.
How about this?

1/3 = .33333333333333333333333333333333333333 etc.
.333333333333333333333333 * 3 = .99999999999999999999999999

3 thirds should equal 1. what the heck?

quote:

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it''s pronounced poo - yaa (long A)
and if you''re even more curious, it means "dynamic" (and yes, that''s my real name)

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I was curious because I knew it meant dynamic, and dynamic is one of my favourite words, but whenever I tried to talk about it being such a cool name, I never knew how to pronounce it.

I think that this should be used as a way to bargain with people when buying stuff (if 1 = .9999999999, then surely you could knock off a dollar or two.... if 1 = .99999999 then surely you could knock off a few more dollars....... if 1 = .99999 and so on ad infinitum)

The other "proof" was when they were telling us that the product of two perpendicular line''s gradients would be equal to -1.

Horizontal line has a gradient of (0 / 1) = 0
Vertival line has a gradient of (1 / 0) = Infinity

So 0 * infinity = -1

From here you can do some weird stuff, like:

multiply by infinity:

0 * infinity * infinity = -1 * infinity

and infinity * infinity = infinity so

0 * infinity = -1 * infinity

then divide by infinity:

0 = -1

And there you have it =)


Trying is the first step towards failure.

But if I have:

0 * infinity = -1 * infinity

which is:

0 = -infinity

then I divide that by infinity, wouldn''t that be:

0 = -1 (because anything divided by itself is 1, and anything divided by the negative of itself is -1)

I love playing around with infinity, it is fun =)


Trying is the first step towards failure.

In case you weren''t listening, I did not mean the limit you fools. I mean recurring. To infinity. That''s why we have bloody limits. Otherwise, instead of bothering with limits we could simply use reccuring numbers. Bloody hell. Doesn''t the limit basically mean:
0.9 with nines going on and on as long as they are not recurring
where as I am talking about it going on forever, until infinity, which does equal one. Everybody knows that.

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Please state the nature of the debugging emergency.

sharewaregames.20m.com

quote:

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Original post by Anonymous Poster
Take some math courses? I just got 58/60 from my final math exam..

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That''s nice. I''m glad you''ve mastered your multiplication tables. Now on to division!

quote:

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Original post by Anonymous Poster
ragonastick, 1/0 is not infinity. In fact, nothing can be ''infinity''. x/0 in just not defined in maths.

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You are so very wrong . Go read up on the algebra of infinity. It''s not very complex so you just might get it. Look up the IEEE Floating Point standard for a simple example.

quote:

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Original post by Anonymous Poster
wise man has spoken

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Surely you jest...

hmmmmm

Actually, Inifinity * 0 != 0...well, not always equal to anyways...infinity is a strange beast.

Pouya, you''re not always right when you say something that I say the opposite to just because you''re older than me.

I was talking about 0.9 with the nine recurring, nothing to do with limits. You haven''t proved me wrong. So go ahead, prove me wrong. Try it. Why don''t you hit me for all I care.

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Please state the nature of the debugging emergency.

sharewaregames.20m.com

Oh, and by the way, I''ve never heard of highschool, whatever that may be. Wait until you get to highschool, and then your grammar might improve.

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Please state the nature of the debugging emergency.

sharewaregames.20m.com