“…This way of thinking could support reasoning about a function defined parametrically, such as (x, y) = (sin10t,cos 20t),0 ≤ t ≤ 1. Thompson used this example to suggest a way of thinking about curves in space, such as (x, y, z) = (sin10t,cos 20t,t),0 ≤ t ≤ 1, by imagining that t is actually an axis, "coming straight at your eyes" (Oehrtman, Carlson, & Thompson, 2008). Thompson proposed that this way of thinking about a curve in space could help the student visualize the graph of the function defined by z = f (x,y), by thinking about y or x as a parameter.…”