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I have no idea what equation or proposition I can use to prove that. I know Z(G)≤G.Is that help?

ldyhome
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2 Answers2

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Use that $G$ is abelian if $G/Z(G)$ is cyclic.

MooS
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HINT: Suppose that $H$ is a subgroup of $G$ of order $4$ contained in the centre of $G$. Show that if $x,y\in G\setminus H$, then $xy=yx$, and conclude that $G$ is Abelian. Note that there must be $h\in H$ such that $y=hx$; why?

Brian M. Scott
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