一个MATLAB 的程序学习

$$\begin{alignedat}{2}10&x+ &3&y = 2 \\ 3&x+&13&y = 4\end{alignedat}$$

$$\overbrace{a+b+c}^{\text{note}}$$

$$\tag{2.1}A=\overbrace{(a+b)+\underbrace{(c+d)i}_{\text{虚数}}}^{\text{复数}}+(e+f)+\underline{(g+h)}$$

$$\tag{2.2}\sum_{i=1}^{n}i=\frac{n(n+1)}{2}$$

$$\tag{2.3}\int_{a}^{b}f(x)dx=F(b)-F(a)$$

$$
\left[
\begin{array}{cc|c}
1&1&1 \\
2&2&2 \\  \hline
3&3&3
\end{array}
\right]
$$

$$
\begin{Vmatrix}
      a5 & b \\
      c & d
\end{Vmatrix}
$$

$$R^2=1-\frac{SS_{res}}{SS_tot}=1-\frac{\sum{(y_i-\hat y_i)^2}}{(y_i-\bar y)^2}$$

$$
\tag{2.4}
\frac{d}{dx}e^{ax}=ae^{ax}\quad\sum_{i=1}^{n}{(X_i - \overline{X})^2}
$$

$$
\begin{aligned}
a_0&=\frac{1}{\pi}\int\limits_{-\pi}^{\pi}f(x)\,\mathrm{d}x\\[6pt]
a_n&=\frac{1}{\pi}\int\limits_{-\pi}^{\pi}f(x)\cos nx\,\mathrm{d}x=\\
&=\frac{1}{\pi}\int\limits_{-\pi}^{\pi}x^2\cos nx\,\mathrm{d}x\\[6pt]
b_n&=\frac{1}{\pi}\int\limits_{-\pi}^{\pi}f(x)\sin nx\,\mathrm{d}x=\\
&=\frac{1}{\pi}\int\limits_{-\pi}^{\pi}x^2\sin nx\,\mathrm{d}x
\\[6pt]
\end{aligned}
$$