飞翔的小聊
幼苗
共回答了11个问题采纳率:90.9% 举报
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)
=1
lim(x→0)(xcot2x)
=lim(x→0)x/tan2x
用等价无穷小
=lim(x→0)x/2x
=1/2
lim(x→∞)(1+(1/2x))^x
=lim(x→∞)(1+(1/2x))^(2x/2)
用重要极限lim(x→∞)(1+1/x)^x=e
=e^(1/2)
=√e
1年前
5