常用等价无穷小

6~sin 3

~tan 2

~sin tan 1

~)1(1

~1ln ~ln ~)1(log ~)1ln(~arctan ~arcsin 2

1~cos 1~tan ~sin 33

32x x x x x x x x x x x x e a x a a

x x x

x x x x x x x

x x n n x x a ---++++++-αββα