有人解答一下吗

不用matlab，用高数直接积分就可以吧

先定义函数：
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function xd = vde(t,x,k,m)

xd = [x(2);-k/m*(x(1))^1.5];
end
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然后程序调用ODE45
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clear;clc;close all;

k = 1e8;
m = 100;
tspan = [0,5];
x0 = [0;1];
[t,x] = ode45(@(t,x) vde(t,x,k,m),tspan,x0);
plot(t,x(:,1))