Question

How can you use a flashlight to make conic sections?

Answer 1

Start with the flashlight parallel to the wall. If you incline it slightly away from the wall, the (conical) beam will still hit the wall and you'll get a hyperbola. It is only after the angle of the flashlight to the wall is greater than the angle of the light cone that the hyperbola vanishes at infinity.

Explanation:

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Answer 2

If you hold it to an angle to a planar surface you will create ellipses....