impossible maths questions (1 Viewer)

ascentyx

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There isn't really anything to prove, isn't it just based on what our definition of 1, 2 and + is. For the 1+0 = 1 though you can use the identity axiom.
 

tommykins

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There isn't really anything to prove, isn't it just based on what our definition of 1, 2 and + is. For the 1+0 = 1 though you can use the identity axiom.
The proof starts from the Peano Postulates, which define the natural
numbers N. N is the smallest set satisfying these postulates:

P1. 1 is in N.
P2. If x is in N, then its "successor" x' is in N.
P3. There is no x such that x' = 1.
P4. If x isn't 1, then there is a y in N such that y' = x.
P5. If S is a subset of N, 1 is in S, and the implication
(x in S => x' in S) holds, then S = N.

Then you have to define addition recursively:
Def: Let a and b be in N. If b = 1, then define a + b = a'
(using P1 and P2). If b isn't 1, then let c' = b, with c in N
(using P4), and define a + b = (a + c)'.

Then you have to define 2:
Def: 2 = 1'

2 is in N by P1, P2, and the definition of 2.

Theorem: 1 + 1 = 2

Proof: Use the first part of the definition of + with a = b = 1.
Then 1 + 1 = 1' = 2 Q.E.D.

Note: There is an alternate formulation of the Peano Postulates which
replaces 1 with 0 in P1, P3, P4, and P5. Then you have to change the
definition of addition to this:
Def: Let a and b be in N. If b = 0, then define a + b = a.
If b isn't 0, then let c' = b, with c in N, and define
a + b = (a + c)'.

You also have to define 1 = 0', and 2 = 1'. Then the proof of the
Theorem above is a little different:

Proof: Use the second part of the definition of + first:
1 + 1 = (1 + 0)'
Now use the first part of the definition of + on the sum in
parentheses: 1 + 1 = (1)' = 1' = 2 Q.E.D.
</pre>
 

sunjai01

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THIS DICKHEAD STOLE MY SIG.

Btw, everyone in this thread should go back and watch Barney the Dinosaur.
SNAP... dude i never kneww u had it.... my bad... if u want ill it take off...
i never saw anyone else in the BoS forum having it.. so i took it....SOZ!



but LOL at the answer above me.... fkn lmao.
at least he showed his working for 1+1=2
 
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omniscience

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how do you know that 1/2 + 1/2 = 1? it can be 5 or 6 or any number

you fail

your solution is basically saying

1+1 = 2 because i want it to be

besides, you cannot use english in maths exam, double fail
 
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EvoRevolution

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how do you know that 1/2 + 1/2 = 1? it can be 5 or 6 or any number

you fail

your solution is basically saying

1+1 = 2 because i want it to be

besides, you cannot use english in maths exam, double fail
if u have a half an apple, then i give u another half apple, and then i give a magic physicmonotermathoographuctelscopicjoinaray to join the halfs togetther u end up with 1 whole apple. omg amazin
 

tommykins

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if u have a half an apple, then i give u another half apple, and then i give a magic physicmonotermathoographuctelscopicjoinaray to join the halfs togetther u end up with 1 whole apple. omg amazin
prove it ?

no problemo einstein

meet me somewhere and ill SHOW U
sure, time and place



it is those who are simply like 'WELL DUH 1+1 = 2' that won't go far in any future mathematics imo.

fundamental proofs are win :)
 

tommykins

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bahahahha how do i know you're not some 40 yr old man trying to rape me.
 

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