一、基本求导公式
常数函数的导数
ddx[c]=0
\frac{d}{dx} [c] = 0
dxd[c]=0
其中 ccc 是常数。
幂函数的导数
ddx[xn]=nxn−1
\frac{d}{dx} [x^n] = n x^{n-1}
dxd[xn]=nxn−1
其中 nnn 是实数。
指数函数的导数
自然指数函数:
ddx[ex]=ex
\frac{d}{dx} [e^{x}] = e^{x}
dxd[ex]=ex
一般指数函数:
ddx[ax]=axlna
\frac{d}{dx} [a^{x}] = a^{x} \ln a
dxd[ax]=axlna
其中 a>0a > 0a>0,a≠1a \neq 1a=1。
对数函数的导数
自然对数函数:
ddx[lnx]=1x,x>0
\frac{d}{dx} [\ln x] = \frac{1}{x}, \quad x > 0
dxd[lnx]=x1,x>0
一般对数函数:
ddx[logax]=1xlna,x>0, a>0, a≠1
\frac{d}{dx} [\log_a x] = \frac{1}{x \ln a}, \quad x > 0, \ a > 0, \ a \neq 1
dxd[logax]=xlna1,x>0, a>0, a=1
三角函数的导数
ddx[sinx]=cosx\displaystyle \frac{d}{dx} [\sin x] = \cos xdxd[sinx]=cosx
ddx[cosx]=−sinx\displaystyle \frac{d}{dx} [\cos x] = -\sin xdxd[cosx]=−sinx
ddx[tanx]=sec2x\displaystyle \frac{d}{dx} [\tan x] = \sec^2 xdxd[tanx]=sec2x
ddx[cotx]=−csc2x\displaystyle \frac{d}{dx} [\cot x] = -\csc^2 xdxd[cotx]=−csc2x
ddx[secx]=secxtanx\displaystyle \frac{d}{dx} [\sec x] = \sec x \tan xdxd[secx]=secxtanx
ddx[cscx]=−cscxcotx\displaystyle \frac{d}{dx} [\csc x] = -\csc x \cot xdxd[cscx]=−cscxcotx
反三角函数的导数
ddx[arcsinx]=11−x2,∣x∣<1\displaystyle \frac{d}{dx} [\arcsin x] = \frac{1}{\sqrt{1 - x^2}}, \quad |x| < 1dxd[arcsinx]=1−x21,∣x∣<1
ddx[arccosx]=−11−x2,∣x∣<1\displaystyle \frac{d}{dx} [\arccos x] = -\frac{1}{\sqrt{1 - x^2}}, \quad |x| < 1dxd[arccosx]=−1−x21,∣x∣<1
ddx[arctanx]=11+x2\displaystyle \frac{d}{dx} [\arctan x] = \frac{1}{1 + x^2}dxd[arctanx]=1+x21
ddx[arccotx]=−11+x2\displaystyle \frac{d}{dx} [arccot x] = -\frac{1}{1 + x^2}dxd[arccotx]=−1+x21
ddx[arcsecx]=1∣x∣x2−1,∣x∣>1\displaystyle \frac{d}{dx} [arcsec x] = \frac{1}{|x| \sqrt{x^2 - 1}}, \quad |x| > 1dxd[arcsecx]=∣x∣x2−11,∣x∣>1
ddx[arccscx]=−1∣x∣x2−1,∣x∣>1\displaystyle \frac{d}{dx} [arccsc x] = -\frac{1}{|x| \sqrt{x^2 - 1}}, \quad |x| > 1dxd[arccscx]=−∣x∣x2−11,∣x∣>1
双曲函数的导数
ddx[sinhx]=coshx\displaystyle \frac{d}{dx} [\sinh x] = \cosh xdxd[sinhx]=coshx
ddx[coshx]=sinhx\displaystyle \frac{d}{dx} [\cosh x] = \sinh xdxd[coshx]=sinhx
ddx[tanhx]=sech2x\displaystyle \frac{d}{dx} [\tanh x] = \text{sech}^2 xdxd[tanhx]=sech2x
ddx[cothx]=−csch2x\displaystyle \frac{d}{dx} [\coth x] = -\text{csch}^2 xdxd[cothx]=−csch2x
ddx[ sech x]=−sech xtanhx\displaystyle \frac{d}{dx} [\ \text{sech} \ x] = -\text{sech} \ x \tanh xdxd[ sech x]=−sech xtanhx
ddx[ csch x]=−csch xcothx\displaystyle \frac{d}{dx} [\ \text{csch} \ x] = -\text{csch} \ x \coth xdxd[ csch x]=−csch xcothx
反双曲函数的导数
ddx[sinh−1x]=1x2+1\displaystyle \frac{d}{dx} [\sinh^{-1} x] = \frac{1}{\sqrt{x^2 + 1}}dxd[sinh−1x]=x2+11
ddx[cosh−1x]=1x2−1,x>1\displaystyle \frac{d}{dx} [\cosh^{-1} x] = \frac{1}{\sqrt{x^2 - 1}}, \quad x > 1dxd[cosh−1x]=x2−11,x>1
ddx[tanh−1x]=11−x2,∣x∣<1\displaystyle \frac{d}{dx} [\tanh^{-1} x] = \frac{1}{1 - x^2}, \quad |x| < 1dxd[tanh−1x]=1−x21,∣x∣<1
二、基本求导法则
常数倍法则
ddx[c⋅f(x)]=c⋅f′(x)
\frac{d}{dx} [c \cdot f(x)] = c \cdot f'(x)
dxd[c⋅f(x)]=c⋅f′(x)
和差法则
ddx[f(x)±g(x)]=f′(x)±g′(x)
\frac{d}{dx} [f(x) \pm g(x)] = f'(x) \pm g'(x)
dxd[f(x)±g(x)]=f′(x)±g′(x)
乘积法则
ddx[f(x)⋅g(x)]=f′(x)g(x)+f(x)g′(x)
\frac{d}{dx} [f(x) \cdot g(x)] = f'(x) g(x) + f(x) g'(x)
dxd[f(x)⋅g(x)]=f′(x)g(x)+f(x)g′(x)
商数法则
ddx[f(x)g(x)]=f′(x)g(x)−f(x)g′(x)[g(x)]2,g(x)≠0
\frac{d}{dx} \left[ \frac{f(x)}{g(x)} \right] = \frac{f'(x) g(x) - f(x) g'(x)}{[g(x)]^2}, \quad g(x) \neq 0
dxd[g(x)f(x)]=[g(x)]2f′(x)g(x)−f(x)g′(x),g(x)=0
链式法则
ddx[f(g(x))]=f′(g(x))⋅g′(x)
\frac{d}{dx} [f(g(x))] = f'(g(x)) \cdot g'(x)
dxd[f(g(x))]=f′(g(x))⋅g′(x)
三、复合函数的导数
幂函数的复合
ddx[u(x)]n=n[u(x)]n−1⋅u′(x)
\frac{d}{dx} [u(x)]^n = n [u(x)]^{n-1} \cdot u'(x)
dxd[u(x)]n=n[u(x)]n−1⋅u′(x)
指数函数的复合
ddx[eu(x)]=eu(x)⋅u′(x)
\frac{d}{dx} [e^{u(x)}] = e^{u(x)} \cdot u'(x)
dxd[eu(x)]=eu(x)⋅u′(x)
对数函数的复合
ddx[lnu(x)]=u′(x)u(x),u(x)>0
\frac{d}{dx} [\ln u(x)] = \frac{u'(x)}{u(x)}, \quad u(x) > 0
dxd[lnu(x)]=u(x)u′(x),u(x)>0
三角函数的复合
ddx[sinu(x)]=cosu(x)⋅u′(x)\displaystyle \frac{d}{dx} [\sin u(x)] = \cos u(x) \cdot u'(x)dxd[sinu(x)]=cosu(x)⋅u′(x)
ddx[cosu(x)]=−sinu(x)⋅u′(x)\displaystyle \frac{d}{dx} [\cos u(x)] = -\sin u(x) \cdot u'(x)dxd[cosu(x)]=−sinu(x)⋅u′(x)
ddx[tanu(x)]=sec2u(x)⋅u′(x)\displaystyle \frac{d}{dx} [\tan u(x)] = \sec^2 u(x) \cdot u'(x)dxd[tanu(x)]=sec2u(x)⋅u′(x)
反三角函数的复合
ddx[arcsinu(x)]=u′(x)1−[u(x)]2,∣u(x)∣<1\displaystyle \frac{d}{dx} [\arcsin u(x)] = \frac{u'(x)}{\sqrt{1 - [u(x)]^2}}, \quad |u(x)| < 1dxd[arcsinu(x)]=1−[u(x)]2u′(x),∣u(x)∣<1
ddx[arccosu(x)]=−u′(x)1−[u(x)]2,∣u(x)∣<1\displaystyle \frac{d}{dx} [\arccos u(x)] = -\frac{u'(x)}{\sqrt{1 - [u(x)]^2}}, \quad |u(x)| < 1dxd[arccosu(x)]=−1−[u(x)]2u′(x),∣u(x)∣<1
ddx[arctanu(x)]=u′(x)1+[u(x)]2\displaystyle \frac{d}{dx} [\arctan u(x)] = \frac{u'(x)}{1 + [u(x)]^2}dxd[arctanu(x)]=1+[u(x)]2u′(x)
双曲函数的复合
ddx[sinhu(x)]=coshu(x)⋅u′(x)\displaystyle \frac{d}{dx} [\sinh u(x)] = \cosh u(x) \cdot u'(x)dxd[sinhu(x)]=coshu(x)⋅u′(x)
ddx[coshu(x)]=sinhu(x)⋅u′(x)\displaystyle \frac{d}{dx} [\cosh u(x)] = \sinh u(x) \cdot u'(x)dxd[coshu(x)]=sinhu(x)⋅u′(x)
ddx[tanhu(x)]=sech2u(x)⋅u′(x)\displaystyle \frac{d}{dx} [\tanh u(x)] = \text{sech}^2 u(x) \cdot u'(x)dxd[tanhu(x)]=sech2u(x)⋅u′(x)
四、高阶导数
二阶导数
f′′(x)=ddx[f′(x)]=d2fdx2
f''(x) = \frac{d}{dx} [f'(x)] = \frac{d^2 f}{dx^2}
f′′(x)=dxd[f′(x)]=dx2d2f
n 阶导数
f(n)(x)=dnfdxn
f^{(n)}(x) = \frac{d^{n} f}{dx^{n}}
f(n)(x)=dxndnf
五、特殊求导技巧
对数求导法
当函数形式为变量的乘积、商或幂次时,可以取对数简化求导过程。
步骤:
取对数:对函数两边取自然对数,lny=lnf(x)\ln y = \ln f(x)lny=lnf(x)。
求导:对等式两边求导,利用链式法则。
1y⋅dydx=ddx[lnf(x)]
\frac{1}{y} \cdot \frac{dy}{dx} = \frac{d}{dx} [\ln f(x)]
y1⋅dxdy=dxd[lnf(x)]
解出导数:
dydx=y⋅ddx[lnf(x)]
\frac{dy}{dx} = y \cdot \frac{d}{dx} [\ln f(x)]
dxdy=y⋅dxd[lnf(x)]
隐函数求导
对于隐式定义的函数 F(x,y)=0F(x, y) = 0F(x,y)=0,求 yyy 关于 xxx 的导数:
dydx=−∂F/∂x∂F/∂y
\frac{dy}{dx} = -\frac{\partial F/\partial x}{\partial F/\partial y}
dxdy=−∂F/∂y∂F/∂x
其中 ∂F/∂x\partial F/\partial x∂F/∂x 和 ∂F/∂y\partial F/\partial y∂F/∂y 分别是 FFF 对 xxx 和 yyy 的偏导数。
参数方程求导
如果 xxx 和 yyy 都是参数 ttt 的函数:
dydx=dy/dtdx/dt,dx/dt≠0
\frac{dy}{dx} = \frac{dy/dt}{dx/dt}, \quad dx/dt \neq 0
dxdy=dx/dtdy/dt,dx/dt=0
六、注意事项
定义域与条件
在应用求导公式时,需注意函数的定义域和适用条件。例如,lnx\ln xlnx 的定义域是 x>0x > 0x>0。
符号与正负
特别是在反三角函数和反双曲函数的导数中,要注意正负号和绝对值的处理。
链式法则的重要性
当遇到复合函数时,一定要使用链式法则,先求外层函数的导数,再乘以内层函数的导数。
高阶导数
在求二阶或更高阶导数时,需反复应用求导法则,并进行适当的简化。