Technology such as Geogebra can give tremendous opportunities to hook students into mathematics if it is introduced as a tool that uses basic mathematics. In the "olden days" one had to have a solid grounding in trig and coordinate geometry to even begin to deal with graphs such as those shown here.
Yes, this does use "cosine". I feel that it could be used to create a desire to find out what this thing called "cosine" really is. As a motivator.
A number of my blog entries have been geared towards using GeoGebra as a math motivator. I will be presenting how some of them were created at the annual conference of the Association of Mathematics Teachers of new York State this fall in Rochester. It'll be fun!!