It’s common for math teachers (and students) to question the topics we spend time on in class.  In certain subjects (*cough* Algebra *cough*), we tend to be particularly pressed for time while attempting to cram what seems like years worth of standards into one, often while stretching below grade level to reach our students.  I can feel myself already veering toward a rant, so I’ll try to ignore some legitimate questions and just address one about cubics. Are cubic polynomials really useful? Heck yes.  For example, robotic joints are controlled by cubic polynomials so they don’t wear out their motors. Consider a robot composed of a single link with one motor-powered joint at its base.  This isn’t just a hypothetical[…]