0,∞0, \infty0,∞
∞,h2\infty, \dfrac{\mathrm{h}}{2}∞,2h
0,h20, \dfrac{\mathrm{h}}{2}0,2h
∞,0\infty, 0∞,0
h2,0\dfrac{\rm{h}}{2}, 02h,0