高数常用公式总结
1. 基础公式
\sin0 = 0,\cos0 = 1;
\ln1 = 0,\ln e = 1,e^0 = 1.
2. 极限
- 极限公式
\lim\limits_{x \rightarrow 0} \frac{sin\,x}{x} = 1 ;
\lim\limits_{x \rightarrow \infty}\left(1+ \frac{1}{x}\right)^x = e ,\lim\limits_ {x \rightarrow 0} (1+x)^ \frac{1}{x} = e ;
\lim\limits_ {x \rightarrow 0} (1+ax)^\frac{b}{x} = e^{ab},\lim\limits_{x \rightarrow \infty} (1+\frac{a}{x})^{bx} = e^{ab}.
- 无穷公式
\lim\limits_ {x \rightarrow 0} \frac{a}{b} = 0,a是b的高阶无穷小
\lim\limits_ {x \rightarrow 0} \frac{a} {b} = \infty,a是b低价无穷小;
\lim\limits_ {x \rightarrow 0} \frac{a} {b} = 1,a是b等价无穷小;
\lim\limits_ {x \rightarrow 0} \frac{a} {b} = m \neq 1,a是b同价无穷小。
3. 导数
- 导数公式
(c)' = 0 \,(c为常数), (x^a)' = ax^{a-1} \,(a为实数);
(a^x)' = a^x\ln a ,(e^x)' = e^x ;
(\log x)'= \frac{1}{x\ln a} , (\ln x)' = \frac{1}{x} ;
(\sin x)' = \cos x ,(\cos x)' = -\sin x ;
(\tan x)'=\frac{1}{\cos ^2 x}=\sec^2 x,(\cot x)'=- \frac{1}{\sin ^2 x}=- \csc ^2 x ;
(\sec x)' = \sec x \tan x , (\csc x)' =- \csc x \cot x;
(\arcsin x)'=\frac{1} {\sqrt{1-x^2}} , (\arccos x)'=-\frac{1}{\sqrt{1-x^2}} ;
(\arctan x)' = \frac{1} {1+x^2},(arccot x)' = {-\frac{1}{1+ x^2}}.
- 四则运算
设u = u(x),v = v(x)在点x处可导,则:
(cu)' = cu' \,(c为常数), (u \pm v)' = u' \pm v' ;
(uv)' = u'v + uv',\left(\frac{u}{v}\right)' = \frac{u'v - uv'}{v^2} \,(v\neq0).
- 复合求导
\frac{dy}{dx} = \frac{dy}{du}·\frac{du}{dx} = f'(u)·g'(x)
4. 微分
- 微分公式
d(c) = 0 \,(c为常数), d(x^a) = ax^{a-1}dx \,(a为实数);
d(a^x) = a^x\ln a dx,d(e^x) = e^xdx ;
d(\log_x) = \frac{1} {x\ln a}dx , d(\ln x)= \frac{1}{x}dx ;
d(\sin x) = \cos xdx ,d(\cos x) = -\sin x dx ;
d(\tan x) =\frac{1} {\cos ^2 x}dx =\sec^2 xdx,d(\cot x) =- \frac{1} {\sin ^2 x}dx=- \csc ^2 x dx;
d(\sec x) = \sec x \tan x dx, d(\csc x) =- \csc x \cot xdx ;
d(\arcsin x) =\frac{1} {\sqrt{1-x^2}}dx , d(\arccos x)={-\frac{1} {\sqrt{1-x^2}}}dx ;
d(\arctan x) = \frac{1} {1+x^2}dx,d(arccot x) = {-\frac {1} {1+x^2}}dx.
- 四则运算
设u = u(x),v = v(x)可微分,则:
d(cu) = cdu \,(c为常数), d(u \pm v) = du \pm dv ,
d(uv) = vdu + udv, d\left(\frac{u}{v}\right) = \frac{vdu - udv} {v^2} \,(v\neq0).
- 复合求导
dy=y'_udu = y'_xdx
5. 洛必达法则
\lim\limits_{x \rightarrow x_0} \frac {f(x)} {F(x)} = \lim\limits_{x \rightarrow x_0} \frac {f'(x)} {F'(x)}= \frac {f'(x_0)} {F'(x_0)},(其中 \frac {f(x)} {F(x)} = \frac {0} {0} 或 \frac {\infty} {\infty})
6.切线方程
- 斜率
k=f'(x_0), k_{切}·k_{法} =-1;
- 点斜式
y-y_0 = k(x-x_0),k为斜率,(x_0,y_0)为切点
- 一元二次方程式
ax^2+bx+c=0, x=\frac{-b \pm \sqrt{b^2-4ac}}{2a}
- 切线方程式
曲线y=f(x)在点(x_0,f(x_0))处的切线方程:
y-f(x_0) =f'(x_0)(x-x_0)
- 法线方程式
当f'(x_0)\neq0时,法线方程:
y-f(x_0) =- \frac {1}{f'(x_0)}(x-x_0)
7. 不定积分
- 基本公式
\int {0}·dx = C, \int{k} dx = kx + C, \int {x^n} dx = \frac{1}{n+1} x^{n+1} + C(n\neq-1) ,\int {\frac{1}{x}dx} = \ln |x|+C , \int {a^x}dx = \frac{1}{\ln a}a^x +C, \int {e^x}dx = e^x +C, \int {\sin x}dx = -\cos x+C, \int {\cos x}dx = \sin x+ C, \int {\frac{1}{\cos ^2 x}}dx = \tan x+C, \int {\frac{1}{\sin ^2 x}}dx = -\cot x+C, \int {\frac{1}{\sqrt{1-x^2}}}dx = \arcsin x+C,\int {\frac{1} {1+x^2}}dx = \arctan x+ C .
- 分部积分公式
\int uv'dx = uv- \int u'vdx
8. 定积分
\int _{a}^{b}f(x)dx = F(x) | _{a}^{b} = F(b)-F(a)
- 分部积分公式
\int _{a}^{b}uv'dx = uv | _{a}^{b} - \int _{a}^{b} u'vdx
9. 变上限积分
y= F(x) = \int _{a}^{x}f(t)dt , F'(x) = f(x)
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