Draw a line ending in an arrow. The slope of that line is: it vertically rises y_rise for every horizontal x_run. The travel is the total horizontal change—it is not the length of the vector, it is the change in x. In the special case of vertical vectors, if (x_run,y_rise)=(0,1), then travel gives the change in y.

For an example see picture.

For elaboration on x_run and y_rise see \line. As there, the values of x_run and y_rise are limited. For \vector you must chooses integers between -4 and 4, inclusive. Also, the two you choose must be relatively prime. Thus, \vector(2,1){4} is acceptable but \vector(4,2){4} is not (if you use the latter then you get a sequence of arrowheads).

© 2007–2018 Karl Berry
Public Domain Software