Proof that 2 = 1



Multiply both sides by a 
a� + a�  2ab = ab + a�  2ab 


Add (a�  2ab) to both sides 

Factor the left, and collect like terms on the right 

Divide both sides by (a�  ab) 

This proof can also be used as a proof by contradiction that a can
never be equal to b.
Related pages in this website
Index of joke proofs
An alternative proof that 2=1
A proof by induction that e =
π
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Graeme McRae.