补充说明:
抽象函数使用洛必达法则最多可用到
基本初等函数的导数公式
( 1 ) ( C ) ′ = 0 ( 3 ) ( sin x ) ′ = cos x ( 5 ) ( tan x ) ′ = sec 2 x ( sec x = 1 cos x ) ( 7 ) ( sec x ) ′ = sec x tan x ( 9 ) ( a x ) ′ = a x ln a ( 11 ) ( log a x ) ′ = 1 x ln a ( 13 ) ( arcsin x ) ′ = 1 1 − x 2 ( 15 ) ( arctan x ) ′ = 1 1 + x 2 ( 17 ) [ ln ( x + x 2 + 1 ) ] ′ = 1 x 2 + 1 注:(17)(18)是推导 ( 2 ) ( x μ ) ′ = μ x μ − 1 ( 4 ) ( cos x ) ′ = − sin x ( 6 ) ( cot x ) ′ = − csc 2 x ( csc x = 1 sin x ) ( 8 ) ( csc x ) ′ = − csc x cot x ( 10 ) ( e x ) ′ = e x ( 12 ) ( ln x ) ′ = 1 x , ( ln ∣ x ∣ ) ′ = 1 x ( 14 ) ( arccos x ) ′ = − 1 1 − x 2 ( 16 ) ( arccot x ) ′ = − 1 1 + x 2 ( 18 ) [ ln ( x + x 2 − 1 ) ] ′ = 1 x 2 − 1 \begin{align*} \begin{aligned} &(1) \ (C)'=0 \\ &(3) \ (\sin x)'=\cos x \\ &(5) \ (\tan x)'=\sec^2x \ (\sec x=\frac{1}{\cos x}) \\ &(7) \ (\sec x)'=\sec x \tan x \\ &(9) \ (a^x)'=a^x \ln a \\ &(11) \ (\log_a x)'=\frac{1}{x \ln a} \\ &(13) \ (\arcsin x)'=\frac{1} {\sqrt{1−x^2}} \\ &(15) \ (\arctan x)'=\frac{1}{\sqrt{1+x^2}} \\ &(17) \ [\ln (x+\sqrt{x^2+1})]'=\frac{1}{\sqrt{x^2+1}} \\ &\text{注:(17)(18)是推导} \\ \end{aligned} \quad \begin{aligned} &(2) \ (x^{\mu})'=\mu x^{\mu−1} \\ &(4) \ (\cos x)'=−\sin x \\ &(6) \ (\cot x)'=−\csc^2x \ (\csc x=\frac{1}{\sin x}) \\ &(8) \ (\csc x)'=−\csc x \cot x \\ &(10) \ (e^x)'=e^x \\ &(12) \ (\ln x)'=\frac{1}{x} ,\ (\ln |x|)'=\frac{1}{x}\\ &(14) \ (\arccos x)'=−\frac{1}{\sqrt{1−x^2}} \\ &(16) \ (\text{arccot} \, x)'=−\frac{1}{1+x^2} \\ &(18) \ [\ln (x+\sqrt{x^2-1})]'=\frac{1}{\sqrt{x^2-1}} \end{aligned} \end{align*} (1) (C)′=0(3) (sinx)′=cosx(5) (tanx)′=sec2x (secx=cosx1)(7) (secx)′=secxtanx(9) (ax)′=axlna(11) (logax)′=xlna1(13) (arcsinx)′=1−x21(15) (arctanx)′=1+x21(17) [ln(x+x2+1)]′=x2+11注:(17)(18)是推导(2) (xμ)′=μxμ−1(4) (cosx)′=−sinx(6) (cotx)′=−csc2x (cscx=sinx1)(8) (cscx)′=−cscxcotx(10) (ex)′=ex(12) (lnx)′=x1, (ln∣x∣)′=x1(14) (arccosx)′=−1−x21(16) (arccotx)′=−1+x21(18) [ln(x+x2−1)]′=x2−11
函数的和、差、积、商的求导法则
设
u
=
u
(
x
)
,
v
=
v
(
x
)
u=u(x),v=v(x)
u=u(x),v=v(x)都可导,则
(1)
(
u
+
v
)
′
=
u
′
±
v
′
(u+v)'=u'±v'
(u+v)′=u′±v′
(2)
(
C
u
)
′
=
C
u
′
(
C
是常数
)
(Cu)'=Cu' \ (C 是常数)
(Cu)′=Cu′ (C是常数)
(3)
(
u
v
)
′
=
u
′
v
+
u
v
′
(uv)'=u'v+uv'
(uv)′=u′v+uv′
(4)
(
u
v
)
′
=
u
′
v
−
u
v
′
v
2
(
v
≠
0
)
(uv)'=\displaystyle\frac{u'v−uv'}{v^2} \ (v≠0)
(uv)′=v2u′v−uv′ (v=0)
复合函数的求导法则
设
u
=
φ
(
x
)
u=\varphi(x)
u=φ(x)在
x
x
x处可导,
y
=
f
(
u
)
y=f(u)
y=f(u)在对应点处可导,则复合函数
y
=
f
[
φ
(
x
)
]
y=f[\varphi(x)]
y=f[φ(x)]在
x
x
x处的导数为
d
y
d
x
=
d
y
d
u
⋅
d
u
d
x
=
f
′
(
u
)
⋅
φ
′
(
x
)
\frac{dy}{dx}=\frac{dy}{du}\cdot\frac{du}{dx}=f'(u) \cdot\varphi'(x)
dxdy=dudy⋅dxdu=f′(u)⋅φ′(x)
隐函数的求导法则
设
y
=
y
(
x
)
y=y(x)
y=y(x)是由方程
F
(
x
,
y
)
=
0
F(x,y)=0
F(x,y)=0所确定的可导函数,为求得
y
′
y'
y′,可在方程
F
(
x
,
y
)
=
0
F(x,y)=0
F(x,y)=0两边对
x
x
x求导,得到一个含有
y
′
y'
y′的方程,从中解出
y
′
y'
y′即可。
另有隐函数求导公式:
d
y
d
x
=
−
F
x
′
F
y
′
\frac{dy}{dx}=-\frac{F'_x}{F'_y}
dxdy=−Fy′Fx′
反函数的求导法则
若
y
=
f
(
x
)
y=f(x)
y=f(x)在某区间内单调可导,且
f
′
(
x
)
≠
0
f'(x)≠0
f′(x)=0,则其反函数
x
=
φ
(
y
)
x=\varphi(y)
x=φ(y)在对应区间内也可导,且
φ
′
(
y
)
=
1
f
′
(
x
)
或
d
x
d
y
=
1
d
y
d
x
\varphi'(y)=\frac{1}{f'(x)} \ 或\ \frac{dx}{dy}=\frac{1}{\displaystyle\frac{dy}{dx}}
φ′(y)=f′(x)1 或 dydx=dxdy1