What is a slope field, and how does it help visualize solutions to a first-order differential equation such as y' = x - y?
A slope field, also called a direction field, is a graphical representation that shows the slopes of solutions to a first-order differential equation at various points in the plane. For an equation like y' = x - y, short line segments are drawn at each point (x, y) with a slope equal to x - y. This allows us to see the general shape and behavior of all possible solution curves, even if we cannot solve the equation analytically.