in contrast, when the function and its inverse are graphed on separate axes, the meaning of the variables and underlying real-world context is clear (see figs. 5a and 5b) Bayazit and Gray(2001) showed that learners with a conceptual understanding of inverse functions were able to deal with the inverse function concept in situations not involving formulas, whereas learners limited by a procedural understanding of inverse functions(e.g., switching x and y) were less likely to be successful in a context without a formula.
Life Expectancies The graphs in figures 6a and 6b show the life expectancies for males and females in the United States based on data and projections from the period 1980-2010(U.S. Census Bureau 2006)