lim(x→0)(1-cos2x)/(x*sin2x)=lim(x→0)2sin²x/(x*sin2x)用等价无穷小=lim(x→0)2x²/(x*2x)=1lim(x→0)(xcot2x)=lim(x→0)x/tan2x用等价无穷小=lim(x→0)x/2x=1/2lim(x→∞)(1+(1/2x))^x=lim(x→∞)(1+(1...