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Hello Operator (Posted on 2003-10-17) Difficulty: 4 of 5
Consider a binary operation # that is closed under the set of integers (if a and b are integers, then a#b is an integer).

Assume that, for all integers a and b, it is true that (a#b)#a=b.

Prove that a#(b#a)=b.

See The Solution Submitted by DJ    
Rating: 4.2727 (11 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
re(2): A simple solution | Comment 7 of 19 |
(In reply to re: A simple solution by SilverKnight)

You say "Commutative means that (a#b)#c = a#(b#c)." That is the associative property. The commutative property is that a#b = b#a.
  Posted by Charlie on 2003-10-19 13:25:13

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