（偏导数的符号用a代替了）两边对x求偏导数：Fx+Fz*az/ax=0az/ax=-Fx/Fz两边对x求偏导数：a^2z/ax^2=-(FxxFz+FxzFz*az/ax-Fx(Fzx+Fzz*az/ax))/Fz^2=-(FxxFz-FxzFz*Fx/Fz-FxFzx+FxFzz*Fx/Fz)/Fz^2=-(FxxFz^2-2FxzFxFz...没太懂啊...我就是-Fx／Fz对x求偏导数算不对...能把这一步再写细点吗＞_＜a^z/ax^2=-(aFx/ax*Fz-Fx*aFz/ax)/Fz^2=-(Fxx*Fz+Fxz*az/ax*Fz-Fx*(Fzx+Fzz*az/ax))/Fz^2第一步是除法的求导，第二步是链式法则