lab7ex1.m

来自「matlab codes for solving ODEs, including」· M 代码 · 共 26 行

function lab7ex1
t0 = 0;
tf = 120;
y0 = -1;
v0 = 0;
[t,Y] = ode45(@f,[t0,tf],[y0,v0]);
y = Y(:,1);
v = Y(:,2);

figure(1);
plot(t,y,'b+-',t,v,'ro-');
legend('y(t)','v(t)=y''(t)');
grid on;

figure(2);
plot(y,v);
xlabel('y');
ylabel('v=y''');
grid on;


function dYdt = f(t,Y)
y = Y(1);
v = Y(2);
dYdt = [ v ; cos(t)-4*abs(y)*v-3*y ];