[求助]双凸透镜

<>双凸透镜两个球面表面的曲率半径均为100mm，沿轴厚度为10mm，玻璃的折射率为1.5，试求其主点、焦点和节点的位置，并绘图表示之。</P>

<></P>
<>各位大侠帮帮忙！！谢了！！！！</P>

为何没人理我

[/IMG]<img src="data/attachment/forum/dvbbs/2004-11/2004112211176100.jpg" border="0" onload="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onmouseover="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.style.cursor=\'hand\'; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onclick="if(!this.resized) {return true;} else {window.open(\'data/attachment/forum/dvbbs/2004-11/2004112211176100.jpg\');}" onmousewheel="return imgzoom(this);" alt="" />

<P>老兄：</P><P>       我是一个门外汉，偶有需求，麻烦你发一个公式过来。我手头连一本参考书都没有！！</P>