8字怎么教孩子写
<img><br>怎样教会孩子写“8”字?<br>“8”象娃娃。从右上碰线到左线成半圆,拐向右下面成圆碰右线,下线、左线,在向上,在中线以上和原线相交,最后,线到右上角附近稍离起笔处为止。不封口。<br><img><br>1 8字笔画笔顺怎么写8<br>数字8的写法:从右进取到左一个半圆,拐向右下,碰右线、下线左线、回上来,在虚线专以上与原线相交,直线到属右上方周边和起笔的地方稍离开了一些为止。<br>2 数字儿歌1-10<br>
版权声明:本文为博主原创文章,遵循 CC 4.0 BY-SA版权协议,转载请附上原文出处链接和本声明。<br>曲线面积的求法:<br>(1)任意曲线的面积求法:<br>>> x=0:pi/100:pi; >> y=sin(x); >> trapz(x,y) ans = 1.9998<br>(2)ROC曲线的面积求法:function auc=auc(FPR,TPR) % given true positive rate and false positive rate calculates the area under the curve % true positive are on the y-axis and false positives on the x-axis % sum rectangular area between all points % example: auc=auc(FPR,TPR); [x2,inds]=sort(FPR); x2=[x2,1]; % the trick is in inventing a last point 1,1 y2=TPR(inds); y2=[y2,1]; xdiff=diff(x2); %xdiff xdiff=[x2(1),xdiff]; auc1=sum(y2.*xdiff); % upper point area auc2=sum([0,y2([1:end-1])].*xdiff); % lower point area auc=mean([auc1,auc2]); end