2.6. If G is a group in which (ab)i = aibi for three consecutive integers i for all a, b ∈ G, show that G is abelian.
2.5. If G is a finite group, show that there exists a positive integer m such that am = e for all a ∈ G.
2.4. If G is a group of even order, prove that it has an element "a\\ne e" satisfying a2 = e.
2.3. Let G be a nonempty set closed under an associative product, which in addition satisfies:
(a) There exists an e ∈ G such that ae = a for all a ∈ G.
(b) Given a ∈ G, there exists an element y(a) ∈ G such that ay(a) = e.
Prove that G must be a group under this product.
Assume that the equation xyz = 1 holds in a group G. Does
it follow that yzx = 1? That yxz = 1? Justify your answer.
2.1. Let S be any set. Prove that the law of multiplication defined
by ab = a is associative.
Test the following numbers for divisibility by 6, 9 and 11. (Do not divide or factorise.)
6 798 340
Which bass -10 (Dienes) block represent the sum of 1034 and 675
If A is a finite set having n elements, prove that A has exactly
2n distinct subsets
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