使用CSDN-markdown写数学公式

CSDN-markdown 写数学公式

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$\sum_{i=0}^n i^2 = \frac{(n^2+n)(2n+1)}{6}$

∑ni=0i2=(n2+n)(2n+1)6

$$\sum_{i=0}^n i^2 = \frac{(n^2+n)(2n+1)}{6}$$

∑i=0ni2=(n2+n)(2n+1)6

$$\sum_{i=0}^n i^2 = \frac{(n^2+n)(2n+1)}{6}$$
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∑i=0ni2=(n2+n)(2n+1)6

$\sum _{i=1} ^d w_ix_i > threshold$
$\sum _{i=1} ^d w_ix_i < threshold$

∑di=1wixi>threshold

∑di=1wixi<threshold

h(x)=sign((∑i=1dwixi)−threshold)=sign((∑i=1dwixi)+(−threshold)w0∗(+1)x0)=sign(∑i=0dwixi)=sign(wTx)

点到直线距离

$$d = \frac{|Ax_0 + By_0 + C|}{\sqrt{(A^2 + B^2)}}$$
$$d = \frac{Ax_0 + By_0 + C}{\sqrt{(A^2 + B^2)}}$$

P(x0,y0),L=kx+b

d=|Ax0+By0+C|(A2+B2)−−−−−−−−√

d=Ax0+By0+C(A2+B2)−−−−−−−−√=A(A2+B2)−−−−−−−−√x0+B(A2+B2)−−−−−−−−√y0+C(A2+B2)−−−−−−−−√=A‘x0+B‘y0+C‘

W⃗ :(A‘B‘),X⃗ :(x0y0),b:C‘

⟹d=WT⋅X⃗ +b

P(x0,y0)带入方程⟹d=⎧⎩⎨d>0,d<0,在L直线正半区在L直线负半区

今天先学到这，改天再补充！