1+1=1? (1 Viewer)

[Anders Englund]

An oldie, but fun:

a = 1
b = 1

This gives us:
a = b

Now multiply both sides by a:
aa = ab
a^2 = ab

Subtract both sides by b^2:
a^2 - b^2 = ab - b^2

The conjugate rule now gives us:
(a + b)(a - b) = ab - b^2

Extract b on the right side:
(a + b)(a - b) = b(a - b)

Divide both sides by (a - b):
a + b = b

or in other words:
1 + 1 = 1



--Anders

 

[Scott L]

You are correct 1+1=1.

 

[Leila Dougan]

Bad math.

You can't do:

Divide both sides by (a - b)

You're dividing by 0, so the answer is undefined.

 

[Morgan Jolley]

You're not supposed to divide by variables for the reason illustrated above. In the step:

Extract b on the right side:
(a + b)(a - b) = b(a - b)

Divide both sides by (a - b):
a + b = b

(a - b) is equal to 0, which means that dividing both sides by 0 would give you an undefined value on both sides. So you haven't done anything special, just broken fundamental rules.

Man, I love math too much.

 

[Mat_M]

Yep, can't divide by zero...I had a math teacher try to pull this on my back in the day, but a few of us caught him.

 

[BrettB]

So, 1 + 1 still = 2?

Thank goodness, what a relief.

 

[Ron-P]

I need a beer!


Peace Out~

 

[dave_brogli]

i was running around going crazy for a sec... i think im still confused

 

[Alex Spindler]

I had a 1+1=1 situation once. Formatting in excel was showing .5 + .5 = 1 as 1 + 1 = 1 because of rounding.

 

[Danny Tse]

Brain ache!!

 

[JayV]

Brain ache!!

IBTL. I'm pretty sure this violates the well-known, no politics, religion or math edict.

-j

 

[Eric_E]

Because the higher the fewer.

 

[MikeAlletto]

The company I used to work for had an ad poster that had:

1+1+1+1=1

It was supposed to mean something and spent thousands and thousands of dollars on some ad company to come up with it, but in the end even the employees never understood what the point was.

 

[Max Leung]

If you didn't know the values of a and b, and you were given a + b = b, it is clear that a and b both cannot be one. In fact, a has to be equal to zero.

We have:

a + b = b

If we want to know what a is, we must subtract b from both sides:

a + b - b = b - b

Therefore:

a = 0

 

[Steven K]

Little Timmy took a drink
But he'll drink no more
Cause what he thought was H2O
Was H2SO4

 

[Wayne Bundrick]

Uh, you're in the wrong classroom. This is math. Chemistry is down the hall. Just follow your nose, the seniors are making stinkbombs.

 

[James T]

We had to do questions similar to 1+1=1 in a Proofs class.

Another question we had on a test was this:

Is it believable that a three-legged chicken can talk?

 

[Shane Bos]

Here I always thought that 1 + 1 = 10

 

[Dave Morton]

What Ron-P said!

 

[MarkHastings]

Shouldn't this be in the Math forum?

I still think the answer is $1.00