lim cosx(1-√(cos2x))/x^2( - 知识问答

lim cosx(1-√(cos2x))/x^2(当x趋于0)是结果是什么,

1个回答

=lim cosx · lim (1-√(cos2x))/x^2
=1 · lim (1-(cos2x))/[x^2 · (1+√(cos2x))]
=lim (1-(cos2x))/[x^2 · lim(1+√(cos2x))]
=lim (1-(cos2x))/[2x^2]
=lim (1/2)(2x)²/[2x^2]
=1

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