Light rays bounce off mirrored walls of a square before reaching one of the other corners. What are the slopes of the light rays leaving A that land in one of the corners B or D after exactly k=5 reflections?

Solution

The slope can be 1/6, 2/5, 3/4, 4/3, 5/2 and 6.

Light rays bounce off mirrored walls of a square before reaching one of the other corners. What are the slopes of the light rays leaving A that land in one of the corners B or D after exactly k=5 reflections? https://t.co/uZdHvS5cFo By @MarshallWBuck pic.twitter.com/ryAlZKlRq4

— Mirangu (@Mirangu1) November 10, 2023