Okie, this question's annoying me 'cause i know it's really easy but I can't get the same answer as is in the back of the textbook:
"Find any turning points on the curve y = (4x^2 - 1)^4 and determine their nature."
I worked out that the stationary points are (0, 1), (0.5, 0) and (-0.5, 0)...