sem+1⁡(x,h2)sem+1′⁡(0,h2)=2m-(1/2)τm+1⁢(Wm+⁡(x)⁢(Pm⁡(x)-Qm⁡(x))-Wm-⁡(x)⁢(Pm⁡(x)+Qm⁡(x))),