我用Latex写公式


上学学过的那些公式,你不会这么快就忘了吧?

公式请到这里写 latexlive

01 初中数学公式

平方差公式

\[(a+b)(a-b)=a^2-b^2\]

完全平方公式

\[(a±b)^2=a^2±2ab+b^2\] \[a^2+b^2=(a+b)^2-2ab\] \[a^3+b^3=(a+b)(a^2-ab+b^2)\] \[(a+b)^3=a^3+3a^2b+3ab^2+b^3\] \[(a+b+c)^2=a^2+b^2+c^2+2ab+2ac+2bc\] \[ab=\frac{(a+b)^2-(a^2+b^2)}{2}=\frac{(a+b)^2-(a-b)^2}{4}\]

一次函数

系数K(斜率) \[k=\frac{y_1-y_2}{x_1-x_2}\]

02 高中数学与高等数学公式

勾股定理

\[a^2+b^2=c^2\]

圆的标准方程

\[(x-a)^2+(y-b)^2=r^2\]

球的体积公式

\[V_球=\frac{4\pi r^3}{3}, (r为半径)\]

球的表面积公式

\[S_球=4\pi r^2, (r为半径)\]

指数

\[a^{m+n}=a^m \cdot a^n \tag{1}\] \[a^{m-n}=\frac{a^m}{a^n} \tag{2}\] \[(ab)^{n}=a^n \cdot b^n \tag{3}\] \[a^{\frac{m}{n}}=\sqrt[n]{a^m} \tag{4}\]

对数

\[a^N = b \Rightarrow \log_{a}{b} = N \tag{1}\] \[\log_a(MN) = \log_aM + \log_aN \tag{2}\] \[\log_a(\frac{M}{N}) = \log_aM - \log_aN \tag{3}\] \[\log_a N = \frac{\log_bN}{\log_ba} (b>0,b\neq1) \tag{4}\] \[\log_a M^n = n \cdot \log_a M \tag{5}\] \[\log_{a^n} M = \frac{1}{n} \cdot \log_a M \tag{6}\]

三角函数常用值

\[\sin 30 ° = \frac{1}{2},\sin45 °=\frac{\sqrt{2}}{2},\sin60 °=\frac{\sqrt{3}}{2} \tag{1}\] \[\cos 30 ° = \frac{\sqrt{3}}{2},\cos 45 °=\frac{\sqrt{2}}{2},\cos 60 °=\frac{1}{2} \tag{2}\] \[\tan 30 ° = \sqrt{3},\cos 45 °=1,\cos 60 °=\frac{\sqrt{3}}{3} \tag{3}\]

三角函数

\[\tan x = \frac{\sin x}{\cos x},\cot x = \frac{\cos x}{\sin x}\]

反三角函数

\[y=\sin x,x=\arcsin y\] \[y=\cos x,x=\arccos y\]

抛物线方程

\[y = ax^2 + bx + c\]\[x = {-b \pm \sqrt{b^2-4ac} \over 2a}\]

直线方程

\[Ax + By + c = 0\]\[y=kx+b\]\[y-y_1=k(x-x_1)\]\[\frac{y-y_1}{y_2-y_1}=\frac{x-x_1}{x_2-x_1}\]\[\frac{x}{a} + \frac{y}{b} = 1\]

三角和差公式

\[\sin(\alpha+\beta) = \sin \alpha \cos \beta + \cos\alpha\sin\beta\] \[\sin(\alpha-\beta) = \sin \alpha \cos \beta - \cos\alpha\sin\beta\] \[\cos(\alpha+\beta) = \cos \alpha \cos \beta - \sin\alpha\sin\beta\] \[\cos(\alpha-\beta) = \cos \alpha \cos \beta + \sin\alpha\sin\beta\] \[\sin \alpha + \sin \beta =2 \sin \frac{\alpha + \beta}{2}\cos \frac{\alpha - \beta}{2}\]

倍角公式

\[\sin2\alpha=2\sin\alpha\cos\beta\] \[\cos2\alpha=2\cos \alpha^2-1=1-2\sin^2\alpha=cos^2\alpha-\sin^2\alpha\] \[\tan 2\alpha=\frac{2\tan\alpha}{1-\tan^2\alpha}\]

微分公式(求导公式)

\[(c)^\prime = 0,(c为常数) \tag{1}\] \[(a^x)^\prime = a^x \ln a \tag{2}\] \[(e^x)^\prime = e^x \tag{3}\] \[(x^n)^\prime = nx^{n-1} \tag{4}\] \[(\log_ax)^\prime = \frac{1}{x\ln a} \tag{5}\] \[(\ln x)^\prime = \frac{1}{x} \tag{6}\] \[(\sin x)^\prime = \cos x \tag{7}\] \[(\cos x)^\prime = -\sin x \tag{8}\] \[(\tan x)^\prime = \frac{1}{\cos^2x} = \sec^2x \tag{9}\] \[(\arcsin x)^\prime = \frac{1}{\sqrt{1-x^2}} \tag{10}\] \[(\cot x)^\prime = -\frac{1}{\sin^2x} \tag{11}\] \[(uv)^\prime=u^\prime \cdot v + u \cdot v^\prime \tag{12}\]

常用积分公式

\[\int k\mathrm{d}x = kx+C \tag{1}\] \[\int x^\mu \mathrm{d}x = \frac{x^{\mu+1}}{\mu+1}+C \tag{2}\] \[\int \frac{1}{x}\mathrm{d}x= \ln \left| x \right| +C \tag{3}\] \[\int \frac{1}{1+x^{2}}\mathrm{d}x= \arctan x +C \tag{4}\] \[\int \frac{1}{\sqrt{1-x^{2}}}\mathrm{d}x= \arcsin x +C \tag{5}\] \[\int \cos x \mathrm{d}x= \sin x +C \tag{6}\] \[\int \sin x \mathrm{d}x= -\cos x +C \tag{7}\] \[\int \frac{1}{\cos^2x} \mathrm{d}x= \tan x +C \tag{8}\] \[\int \frac{1}{\sin^2x} \mathrm{d}x= -\cot x +C \tag{9}\] \[\int \sec x \tan x \mathrm{d}x= \sec x +C \tag{10}\] \[\int \csc x \cot x \mathrm{d}x= -\csc x +C \tag{11}\] \[\int e^x \mathrm{d}x= e^x +C \tag{12}\] \[\int a^x \mathrm{d}x= \frac{a^x}{\ln a} +C \tag{13}\] \[\int sh x \mathrm{d}x= ch x +C \tag{14}\] \[\int ch x \mathrm{d}x= sh x +C \tag{15}\]

不定积分

\[\int f(x)\mathrm{d}x = F(x) + c\]

牛顿-莱布尼兹公式

如果函数(f(x))在区间([a,b])上连续,并且存在原函数(F(x)),则 \[\int_a^b f(x)\mathrm{d}x = F(b)-F(a)=F(x)|_a^b\]

齐次方程公式

\[{ dy \over dx} = u + x { du \over dx}\]

三角函数积分

\[\sin x = { 2u \over 1 + u^ 2}\] \[\cos x = { 1-u^2 \over 1 + u^ 2}\]

全微分公式

\[dz = {{\partial z} \over {\partial x}}dx + { {\partial z} \over {\partial y}}dy\] \[du = {{\partial u} \over {\partial x}}dx + { {\partial u} \over {\partial y}}dy + { {\partial u} \over {\partial z}}dz\]

两个重要极限

\[\lim_{x \to 0} \frac{\sin x}{x}=1 \tag{1}\] \[\lim_{x \to \infty} (1+\frac{1}{x} )^x = e \tag{2}\]

常用极限

\[\lim_{x \to \infty} \sqrt[x]{a} = 1\] \[\lim_{x \to \infty} \sqrt[x]{x} = 1\]

分部积分法

\[\int u \frac{\mathrm{d}v}{\mathrm{d}x}\,\mathrm{d}x=uv-\int \frac{\mathrm{d}u}{\mathrm{d}x}v\,\mathrm{d}x\] \[\int u \mathrm{d}v = u \cdot v - \int v \mathrm{d}u\]

旋转体的体积计算

\[\int \pi f^2(x) \mathrm{d}x\]

二重积分

\[\iint_{a}^{b} f(x,y) \mathrm{d}x \mathrm{d}y\] \[\int_{0}^{1} \mathrm{d}y \int_{0}^{1} f(x,y) \mathrm{d}x\] \[\iint\limits_D dx\,dy\]

常数项级数

\[\sum_{n=1}^{\infty}{u_n}\]

等比级数、调和级数、P级数

幂级数

\[a_0+a_1x+a_2x^2+\cdots+a_nx^n+\cdots= \sum_{n=1}^{\infty}{a_nx^n}\]

收敛半径

\[R=\frac{1}{\rho}=\frac{u_{n+1}}{u_n}\] \[\rho= \lim_{n \to +\infty}|\frac{a_{n+1}}{a_n}|\]

傅里叶级数

行列式计算

\[\begin{vmatrix} 1 & 2 & 3\\ 4 & 5 & 6\\ 7 & 8 &9 \end{vmatrix}=1×5×9+2×6×7+3×4×8-(3×5×7+2×4×9+6×8×1)=n\]

矩阵

\[\begin{bmatrix} 1 & 2 & 3\\ 4 & 5 & 6\\ 7 & 8 &9 \end{bmatrix}\]

排列组合公式

\[\mathrm{A}_n^m=\frac{n!}{(n-m)!} \tag{排列公式}\] \[\mathrm{C}_n^m=\mathrm{C}_n^{n-m}=\frac{A_n^m}{m!} \tag{组合公式}\]

二项式系数

\[\dbinom{n}{r}=\binom{n}{n-r}=\mathrm{C}_n^r=\mathrm{C}_n^{n-r}\]

齐次线性方程组

\[\begin{cases} 3x + 5y + z \\ 7x - 2y + 4z \\ -6x + 3y + 2z \end{cases}\] \[\left\{\begin{aligned} 3x + 5y + z \\ 7x - 2y + 4z \\ -6x + 3y + 2z \end{aligned}\right.\] \[f(x)=\begin{cases} 1, & x>0\\ 0, & x=0\\ -1, & x<0 \end{cases}\]

等差数列公式

\[a_{n}=a_{1}+ \left( n-1 \left) d\right. \right.\]

等差数列的前N项和

\[S_{n}=\frac{n \left( a_{1}+a_{n}\right)}{2}=na_{1}+\frac{n \left( n-1 \right)}{{2}}d\]

等比数列公式

\[a_{n}=a_{1}q^{n-1}\]

等比数列的前N项和

\[S_{n}=\frac{a_1(1-q^n)}{1-q}=\frac{a_1+a_nq}{1-q}\]

等差中项

\[2b=a+c,(a,b,c为等差数列)\]

等比中项

\[b^2=a \cdot c,(a,b,c为等比数列)\]

裂项相消法

\[若 \frac{1}{n(n+1)}=\frac{1}{n}-\frac{1}{n+1},则有T_n=1-\frac{1}{n+1}=\frac{n}{n+1} \tag{1}\]

二项式定理

\[(a+b)^n=C_{n}^{0}a^n+C_{n}^{1}a^{n-1}b^1+C_{n}^{2}a^{n-2}b^2+\cdots+C_{n}^{k}a^{n-k}b^k+\cdots+C_{n}^{n}b^n\] \[(a+b)^n=\sum_{r=0}^{n}{C_{n}^{r}a^{n-r}b^r}\]

二项展开式的通项

\[T_{r+1}=C_{n}^{r}a^{n-r}b^r\]

两点之间的距离公式

\[|AB| = \sqrt{(x_1-x_2)^2+(y_1-y_2)^2+(z_1-z_2)^2}\]

平面方程

\[Ax+By+Cz+D=0\]

平面的点法式方程

\[A(x-x_0)+B(y-y_0)+C(z-z_0)=0\]

直线与平面的夹角

\[\sin \theta=\frac{Al+Bm+Cn}{\sqrt{A^2+B^2+C^2} \cdot \sqrt{l^2+m^2+n^2}}\]

两平面的夹角

\[\cos \theta=\frac{A_1A_2+B_1B_2+C_1C_2}{\sqrt{A_1^2+B_1^2+C_1^2} \cdot \sqrt{A_2^2+B_2^2+C_2^2}}\]

点到平面的距离公式

\[d=\frac{|Ax_0+By_0+Cz_0+D|}{\sqrt{A^2+B^2+C^2}}\]

点到直线的距离

\[d=未写\]

椭圆和双曲线

\[\frac{x^{2}}{a^{2}}+\frac{y^{2}}{b^{2}}=1\]\[\frac{x^{2}}{a^{2}}-\frac{y^{2}}{b^{2}}=1\]

极坐标公式

在极坐标中,\( \rho \)表示长度,取值范围[0,+∞),\( \theta \)表示角度,取值范围[0,2π)或[-π,π]

\[\left\{\begin{matrix} x= \rho \text{cos}\theta \\ y= \rho \text{sin}\theta \end{matrix}\right.\]\[\rho = \frac{1}{ \sin \theta + \cos \theta}\]\[\left\{\begin{matrix} x=a + r\text{cos}\theta \\ y=b + r\text{sin}\theta \end{matrix}\right. \tag{圆的参数方程}\]

概率的五个计算公式

\[P(A \cup B)=P(A)+P(B) - P(A \cap B)\]\[P(A - B)=P(A\bar{B})= P(A) - P(AB)\]\[P(AB)=P(A)P(B|A)\]