"quasi" <email@example.com> wrote in message news:firstname.lastname@example.org... > John Smith wrote: >> >>A recent thread about points of inflection reminded me of >>a function I encountered when I was a math student. >> >>The function had many points of inflection but it also had >>points, which I presume are also called inflection points, >>where the gradient was infinite (i.e tending to a vertical >>rather than horizontal line on an x,y graph). >> >>I remember the graph looking like a staircase with rounded >>edges but I have completely forgotten what the function was. >>It's possible I have not remembered it correctly due to it >>being so long ago. >> >>Can anyone tell me what this function was or give me a >>similar function? > > The curve given by the implicit equation > > x - y = sin(x + y) > > has the shape you described.
Thanks, that looks very like what I remember but I can't remember whether it was horizontal or vertical at the origin. It would have had to have been in a form which I could plot manually on graph paper in less than an hour at age about 18.
> > In Wolfram Alpha, try: > > plot x - y = sin(x + y) > > quasi