The inverse of the point (1,2) which is found
by interchanging the two coordinates (2,1). It
always amounts to a reflection in the 45-degree
line through the origin, the line whose equation is
y = x. The red curve and the green curves below
are inverses of each other. The red curve is the
graph of f and green curve is the graph of f-1.
The dotted blue line is the line y = x, which is
often called "the identity line". The graph of f,
the red curve, contains the point (1,2) and the
graph of f-1, the green curve, contains
the inverse point (2,1), where the coordinates are
interchanged.
Edwin
