clc,syms t v m b g a x = v*m*cos(a)/b*(1-exp(-b*t/m)); y = (m^2*g/b^2 + m*v*sin(a)/b)*(1-exp(-b*t/m))-m*g*t/b y=subs(compose(y,finverse(x)),'t','x') pretty(y)
答案是
y = - ((g*m^2)/b^2 - (v*sin(a))/(cos(a)*(exp(-(b*x)/m) - 1)))*(exp(-(b*x)/m) - 1) - (g*m*x)/b
至于 x = x(y) 你只需要用finverse命令将y转化为它的反函数就可以了
参考 ：http://user.qzone.qq.com/184908480/2