This applet use another representation to show 1/p+1/q=1/f

You can drag p in the plotting panel and find out the q easily from intersection point at the y-axis.
You can drag and change the focus point,too.

/htdocs/ntnujava/ejsuser/2/users/ntnu/fkh/pqf_pkg/pqf.propertiesFull screen applet or Problem viewing java?Add to exception site list
Press the Alt key and the left mouse button to drag the applet off the browser and onto the desktop. This work is licensed under a Creative Commons Attribution 2.5 Taiwan License
Download EJS jar file(1329kB):double click downloaded file to run it. (65 times by 38 users) , Download EJS source (25 times by 19 users) View EJS source