- Dec 2006
You seem to be misreading the graph. The parabola shown is for y = xÂ²/2 - 1/12.The obvious flaw on this Wiki page . . . If you look at every other point on these graphs, such as x=0.5, x=1.5, x=2.5, x=3.5 and x=4.5, all match the graph for y=(x-0.5)(x+0.5)/2, and this has a y-intercept at -1/8.