This activity is also part of one or more other Books. Modifications will be visible in all these Books. Do you want to modify the original activity or create your own copy for this Book instead?
This activity was created by '{$1}'. Do you want to modify the original activity or create your own copy instead?
This activity was created by '{$1}' and you lack the permission to edit it. Do you want to create your own copy instead and add it to the book?
Dandelin's theorem
* Move points A and B to change section of the cone
* Spheres are tangent to the plane and to the cone
* Move point P on the conic
* When the conic is an ellipse, why is MP+PH constant ?