proof that 2+2 = 5 weird

abeja0123 · Dec 10, 2011

Full proof without mind cuts :]
(just copied and added few more lines)

Start with: -20 = -20
Which is the same as: 16-36 = 25-45
Which can also be expressed as: (2+2)^2 - 9 x (2+2) = 5^2 - 9 x 5
Add 81/4 to both sides: (2+2)^2 - 9(2+2) + 81/4 = 5^2 - 9 x 5 + 81/4
Rearrange the terms: [(2+2)- 9/2)]^2 = (5-9/2)^2
this is because... [(2+2)- 9/2)]^2 = [(2+2) - 9/2][(2+2) - 9/2]= (2+2)^2 + 81/4 - 9 - 9 -9 -9= (2+2)^2 - 9(2+2) + 81/4
and... (5-9/2)^2= (5- 9/2)(5-9/2) = 5^2+81/4 - 45/2 - 45/2= 5^2+81/4 - 45 = 5^2+81/4 - 9x5
Square root the equation: [(2+2) - 9/2)]^2 = (5-9/2)^2 to get (2+2) - 9/2 = 5 - 9/2
Add +9/2 to both sides to get:
2+2= 5

alexan_e · Dec 10, 2011

SQRT(a²) = |a| (absolute value of a)

so √[(2+2)-(9/2)]² = √[5-(9/2)]²
becomes |(2+2)-(9/2)| = |5-(9/2)|

and not (2+2) - 9/2 = 5 - 9/2

Read post #19 https://www.edaboard.com/threads/192478/#post833679

Alex

abeja0123 · Dec 11, 2011

alexan_e said:
SQRT(a²) = |a| (absolute value of a)

so √[(2+2)-(9/2)]² = √[5-(9/2)]²
becomes |(2+2)-(9/2)| = |5-(9/2)|

and not (2+2) - 9/2 = 5 - 9/2

Sorry forgot about that
hmm but than... if you add 9/2 to both sides does it still work?

Microwave123 · Dec 19, 2011

No. According to order of operation, you must do the math inside the absolute value bracket first.

Sheniqua · May 2, 2012

lightning r fun said:
here is one that works better:
-20=-20 (it is fact)
16-36=25-45 (16-36=-20,25-45=-20)
4^2-36 = 5^2-45 (4^2=16,5^2=25)
4^2-36 = 5^2-45
4^2-2.4.9/2 = 5^2-2.5.9/2 (2.4.9/2=36,2.5.9/2=45)
4^2-2.4.9/2 +(9/2)^2 = 5^2-2.5.9/2 +(9/2)^2 (adding both the sides (9/2)^2
[4-(9/2)]^2 = [5-(9/2)]^2 (let 4=a,9/2=b)
4-(9/2) = 5-(9/2)
4 = 5
2+2 = 5

---------- Post added at 11:35 ---------- Previous post was at 11:34 ----------

here's another one

Let x be a non-zero number, and set y=x. Thus:
x = y
x^2 = xy
x^2-y^2 = xy-y^2
(x+y)(x-y) = y(x-y)
x+y = y
2y = y
2 = 1
1 = 0
Now since 2+2 = 2+2+0 and we apply the lemma proof so that 0 = 1, 2+2+0 = 2+2+1 =5
THEREFORE
2+2 = 5

First off, the square root of a number leaves the possibility of it being positive or negative so
(5-9/2)^2 = (4-9/2)^2
+- (-.5) = +- (.5)
Giving you
-.5=-.5
Or
.5=.5
Or
|.5|=|.5|

And

If x = y
Then x - y = 0
And you can't divide by zero so
(x+y)(x-y) = y(x-y)
Is not
x+y = y

rajput9571 · Aug 18, 2012

lightning r fun said:
Start with: -20 = -20
Which is the same as: 16-36 = 25-45
Which can also be expressed as: (2+2) 2 (9 X (2+2) = 52) 9 X 5
Add 81/4 to both sides: (2+2) 2 (9 X (2+2) + 81/4 = 52) 9 X 5 + 81/4
Rearrange the terms: ({2+2}) 9/2) 2 = (5-9/2) 2
Ergo: 2+2 - 9/2 = 5
Hence: 2 + 2 = 5

It's so weird title and I am not getting how do you solve this type of problems. I think you should express 3rd line in well matter and why we go through this equation?
**broken link removed**

Magvitron · Aug 18, 2012

post # 9
x = y
x^2 = xy
x^2-y^2 = xy-y^2
if you have to apply x^2-y^2 = (x+y)(x-y) x must not be equal to y. ie. x-y will be xero.
same to the post #1
its something called mathematical fallacy love the name.. sounds dreamy ;-)
check it out
https://en.wikipedia.org/wiki/Mathematical_fallacy

BradtheRad · Aug 18, 2012

Here's a formula known as Euler's equation. It's for real and it is paradoxical.

E is the well known important constant which is the base of natural logarithms.

I is the square root of minus 1.

https://betterexplained.com/articles/intuitive-understanding-of-eulers-formula/

Froginthewell · Aug 18, 2012

At last moment, taking the square root is the part when above proof gets messy.
On doing so, you have only considered the positive sign.
Actually x^2=4 is x=+2 or -2.
You didn't take the negative part.
Also remember that both the results are not necessary to be true.
Only one may be true.
Here you chose the false one i.e. positive part.
Every mathematics that leads to absurd result arise from some misconception and mistakes.

mrflibble · Aug 18, 2012

BradtheRad said:
Here's a formula known as Euler's equation. It's for real and it is paradoxical.

E is the well known important constant which is the base of natural logarithms.

I is the square root of minus 1.

https://betterexplained.com/articles/intuitive-understanding-of-eulers-formula/

And why should that be paradoxical?

- - - Updated - - -

Also, just for the fun of it, calculate i^i. That neatly ties i, pi, and e together.

jeffrey samuel · Aug 18, 2012

mrflibble said:
Also, just for the fun of it, calculate i^i. That neatly ties i, pi, and e together.

can you prove it out and state how they are tied to each other

BradtheRad · Aug 18, 2012

Here's a webpage calling Euler's formula 'a beautiful equation':

**broken link removed**

Quote:

"Euler's equation expresses a universal truth, valid in any language or culture. It contains five of the most important numbers in maths: 0, 1, e, i, and π, along with the fundamental concepts of addition, multiplication, and exponentiation. These vital numbers and concepts also crop up in branches of science, engineering, and technology. All these ideas in just a few squiggles - if that's not beautiful, what is?"

tpetar · Aug 18, 2012

This Euler's equation bankers apply to peoples loan interest rates plus coefficient of multiplication.

mrflibble · Aug 19, 2012

jeffrey samuel said:
can you prove it out and state how they are tied to each other

There is nothing much to "prove" there. It's just a little fun identity when you write out i^i. As in basically just a little shuffling of terms. Anyways, the result being this:

i^i = exp(-pi/2)

which I found cute.

Bogdan Vilicic · Dec 28, 2012

2 +2 = 5

John has 02 bags of sugar of 1.25 kg each.
Maria has 02 bags of sugar of 1.25 kg each.

02 bags + 02bags = 04bags = 05kg

therefore:

02 +02 = 05

The relativity of Einstein in physics shows that the perception of the world depends on the viewpoint of the observer.

In mathematics is also possible to give a different result depending on how conventional applies equation.

02 bags of sugar plus two bags of sugar is equal to five 5kg of sugar.

hugs,

Bogdan

sam_r · Jan 11, 2013

Please dont violate the very basic operations. Division by zero is not defined.

- - - Updated - - -

Please dont violate the very basic operations. Division by zero is not defined.

- - - Updated - - -

Please dont violate the very basic operations. Division by zero is not defined.

proof that 2+2 = 5 weird

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