hi all, I am a bit confused. The graph of y=Sinhx seems to have a point of inflection about x=0. However if I differentiate this function then y'=Coshx and Coshx does not ever equal zero, bringing me to the conclusion that there are no turning points on that graph?? The website http://nrich.maths.org/2377&part=solution describes the point at the origin as a point of inflection also??