Self-navigating robots are very useful in the real world. Reducing the risk of human error by having a computer do tasks can increase the safety of transportation: Airplanes have systems that automate takeoffs and landings. Some cars can parallel park themselves. Cargo ships have autopilots. Mazes offer a challenge that can be directly translated to these situations. In this task, you are developing navigation software for a company that makes robotic systems that can direct themselves. As a first-level test of the robot you are developing, you will have it navigate a maze.

Part A

When navigating the maze, the robot will only need to go north, south, east, and west. It can be useful to use the complex plane to represent these directions. When using the complex plane this way, we use numbers such that their magnitude is equal to 1. If we let the value i represent the robot facing due north, what values represent the robot facing east, south, and west?

Part B

The arrow at the maze entrance indicates that the robot will be heading east when it enters the maze. When programming the robot, let the complex number d represent the direction the robot is facing. As the robot changes direction, the value of d will also change; so, the value of d is dependent on where the robot is in the maze. At the start of the maze, what is the value of d?

Part C

While navigating the maze, the robot will need to be able to turn left and right. The first turn the robot will make is a left turn. What will the value of d be after the first turn?

Part D

When the robot makes a turn, it would be useful to have an operation to perform on d to represent this turn. This is because after making a turn, the new value of d will depend on the old value of d. Complete the table for the new values of d if the robot is turning left or right. Then determine an expression in terms of d that will give the new position if the robot turns left and another expression if the robot turns right. Type these expressions in the last row of the table.

Initial d: Left Turn: Right Turn:
-1
1
i
-i
d

Part E

Given the answer for part D, create an expression that will tell you the direction the robot is going if, in the course of its journey, it turns left 21 times and turns right 22 times. Does the order the robot makes the turns in matter for the purpose of knowing the direction it is finally facing?