x=t+2,y=2t+1

微分方程 矩阵 x'(t)=x(t)+y(t)+2t y'(t)=x(t)+y(t)-2t 叶形线：x=2*t-t*t,y=2*t*t-t*t*t 图形怎么划? x=2t+1/t,y=t-1/2t参数方程, x = t - ln(1+t) y = t^3 + t^2 求dy/dx matlab solve的用法S=dsolve('Dx=450*(90*t-x)/sqrt((90*t-x)^2+(120-y)^2),Dy=450*(120-y)/sqrt((90*t-x)^2+(120-y)^2)')结果：[y(t)=120,x(t)=450*t+C1,y(t)=120,x(t)=-450*t+C1,[((90*t-x(t))^2/diff(x(t),t)^2)^(1/2)=(90*t-x(t))/diff(x(t),t),y(t)=(120*dif x=t+2,y=2t+1 已知X=t+1,y=2t-1 x=2t-t*t y=3t-t*3的拐点是什么? 已知x=2t/1+t,y=t/1-t,用x的代数式表示y 设x=t^2-1,y=t^4-2t^3,求y 将x=1-t/1+t y=2t/1+t(t为参数）化为普通方程 matlab求解微分方程组x'(t)/(x(t)-300*t/sqrt2)=y'(t)/y(t)---方程(1)x'(t)/(x(t)-300*t/sqrt2)=z'(t)/(z(t)-300*t/sqrt2）---方程（2）(x'(t))^2+(y'(t))^2+(z'(t))^2=360000---方程（2）但是提示有错误.高手帮忙看看错在哪里.要 高数题设x=(t+1)e^t,y=t^2*e^t,求d^2y/dx^2 [T,Y]=ode45(@rigid,[0 1],[rand(15,1)]);plot(T,Y(:,1),'-',T,Y(:,2),'-.',T,Y(:,3),'.',T,Y(:,4),'-',T,Y(:,5),'-.',T,Y(:,6),'.',T,Y(:,7),'-',T,Y(:,8),'-.',T,Y(:,9),'.',T,Y(:,10),'-',T,Y(:,11),'-.',T,Y(:,12),'-.',T,Y(:,13),'.',T,Y(:,14),'-',T,Y(:,15),'.') y=根号t^2+1 x=t-1/根号t^2+1的导数 x=2/1+t²,y=2t/1+t²的参数方程 已知{x=3t^2+1,y=t^6+2t^3},求导数 mathematica编程哪里错啦,急~~NDSolve[{y''[t] == -9.81, y[0] == 11, y'[0] == 0, x[t] = 1.5 t, WhenEvent[y[t] == 0, y'[t] -> -0.80 y'[t]], WhenEvent[y[t] == 0, x'[t] -> -0.80 x'[t]], WhenEvent[ Abs[y'[t]] < 1*10^(-6), {tf = Sqrt[x^2 +