managers should never forget ehat variable and fixef cost-behavior patterns are valid for linear cost function only within a given relevant range. outside the relevant range, variable and fixed cost-behavior patterns change, causing cost to become nonlinear(nonlinear means the plot relationship on a graoh is not a straight line).for example,exhibit 10-2 plots the relationdhip (over several years) between total direct manufacturing labor costs and the munber of snowboards produced each year by ski authority at its vermont plant. in this case, the nonlinearities outside the relevant rang occur because of labro and other infficiencies (first brcause workers are learning to produce snowb0ards and later beceuse capacity limits are being stretched). knowing the relevsnt range is essential to properly clssify costs