You are driving along a perfectly straight road through the woods and decide the trees look like an inviting hike. After all, you have a GPS that could easily get you back to the road. So you get out and head off in a straight line perpendicular to the road, not paying any attention to your direction because, hey, GPS.
Unfortunately after traveling 1km your GPS crashes. It loses all of its map data as well as any previous journeys. In you panic, you even forgot which direction you were walking.
So here you are: 1 km away from the long straight road (the only one around for many km) in an unknown direction. You have a GPS that can still give your accurate position and path relative to your start.
What is the length of the shortest path (measured from here) that guarantees you will find the road?
Note: the trees are dense enough that you could be very close to the road and not see it.
(In reply to re: proposed solution
As the problem is to find the road and not the car in the shortest distance, walk the following path until the the road is found.
Walk straight in some direction for SQRT(2) kilometers, then turn 135 degrees and walk 1 kilometer, then begin walking in a half-circle with the starting point being the circle's center, and then, again, walk straight for 1 km a path that is parallel to the second leg of the trek. The total distance walked is [SQRT(2) + 1 + PI + 1] kilometers, or approximately 6.555806 km.
Posted by Dej Mar
on 2016-01-09 09:54:33