来自贺小亮的问题
【当x趋向于0,sin2x-2sinx与x的k次方是同阶无穷小量,求k】
当x趋向于0,sin2x-2sinx与x的k次方是同阶无穷小量,求k
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【当x趋向于0,sin2x-2sinx与x的k次方是同阶无穷小量,求k】
当x趋向于0,sin2x-2sinx与x的k次方是同阶无穷小量,求k
当x→0时lim(x→0)(sin2x-2sinx)/x^k=lim(x→0)2sinx(cosx-1)/x^k=-4lim(x→0)sinx[sin(x/2)^2]/x^k=-8lim(x→0)cos(x/2)[sin(x/2)^3]/x^k=-8lim(x→0)[sin(x/2)^3]/x^k=-lim(x→0)[sin(x/2)/(x/2)]^3×(x^3/x^k)=-l...