kiky 发表于 2006-1-2 17:24

数学问题编程求教

用两种方法（符号法，数值法）求解平面曲线y=sin(x+xsinx)在上的长度！<BR><BR>

yqchenlolo 发表于 2006-1-2 18:33

&gt;&gt; int(sqrt(1+diff('sin(x+x*sin(x))')^2),0,2*pi)<BR>Warning: Explicit integral could not be found.<BR>&gt; In C:\matlab6p5\toolbox\symbolic\@sym\int.m at line 58<BR> <BR>ans =<BR> <BR>int((1+cos(x+x*sin(x))^2*(1+sin(x)+x*cos(x))^2)^(1/2),x = 0 .. 2*pi)<BR>符号方法没有显式解<BR>数值方法：<BR>sum=0;<BR>for n=1:200<BR>sum=sum+pi/200*subs(sqrt(1+diff('sin(x+x*sin(x))')^2),'x',n*pi/200);<BR>end

kiky 发表于 2006-1-2 20:51

<P>我也是符号方法做不出显式解<BR></P>

happy 发表于 2006-1-3 11:39

回复：（kiky）数学问题编程求教

看帖子<a href="http://vib.hit.edu.cn/vibbbs/dispbbs.asp?boardID=35&amp;ID=6476&amp;page=1" target="_blank" >http://vib.hit.edu.cn/vibbbs/dispbbs.asp?boardID=35&amp;ID=6476&amp;page=1</A>
页: [1]
查看完整版本: 数学问题编程求教