当 $x\rightarrow0$ 时
(02) $ \tan x \backsim x $
(01) $ \sin x \backsim x $
(03) $ \arcsin x \backsim x $
(04) $ \arctan x \backsim x $
(05) $ \ln(1+x) \backsim x $
(06) $ e^{x} -1 \backsim x $
(07) $ 1-\cos x \backsim \frac{1}{2}x^{2} $
(08) $ x – \ln(1 + x) \backsim \frac{1}{2}x^{2} $
(09) $ \tan x – \sin x \backsim \frac{1}{2}x^{3} $
(10) $ \arcsin x – \arctan x \backsim \frac{1}{2}x^{3} $
(11) $ \tan x – x \backsim \frac{1}{3}x^{3} $
(12) $ x – \arctan x \backsim \frac{1}{3}x^{3} $
(13) $ x – \sin x \backsim \frac{1}{6}x^{3} $
(14) $ (1+a)^{x}-1 \backsim ax $
(15) $ a^{x}-1 \backsim \ln a\times x $