Question

求极限，大神解答

Answer 1

(4)
lim (tanx-sinx)/x³
x→0
=lim [x+⅓x³-(x- (1/6)x³)]/x³
x→0
=lim ½x³/x³
x→0
=½

Answer 2

用万能公式
=2tan(x/2)/(1+tan²(x/2))x³ + 2tan(x/2)/(1-tan²(x/2))x³
这样就能用tanx ~ x了
=4tan(x/2)/8(1 - tan(x/2)四次方)(x/2)³ = 1/2