y=(t^2-t+1) / (t^2+t+1) .t等于多少时,y取到0

微分方程 矩阵 x'(t)=x(t)+y(t)+2t y'(t)=x(t)+y(t)-2t y=t/t^2+t+1的最大值 [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),'.') 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, y=(t^2-t+1) / (t^2+t+1) .t等于多少时,y取到0 x = t - ln(1+t) y = t^3 + t^2 求dy/dx t小于0,求y=(t^2-4t+1)/t的最大值 t>0,y=(t^2-4t+1)/t最小值 t>0,y=(t^2-4t+1)/t的最小值是 已知t>0,则函数y=(t^2-4t+1)/t的最小值为 x=2t-t*t y=3t-t*3的拐点是什么? y=-2t²+5t-2 求t y=(t^2+t-4)/t的值域 将x=1-t/1+t y=2t/1+t(t为参数）化为普通方程 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 用解析法求下列二阶微分方程(1) y(t) + 4y(t) + 3y(t) = f (t),f (t) = ε (t)(2) y(t) + 4y(t) + 4y(t) = f '(t) + 3 f (t),f (t) = e−tε (t)注：e-t为e的-t次方其中ε (t)为阶跃函数,即当t0时,ε (t)=1 matlab中怎么对下面的程序进行二维插值并画出三维视图呢?[x,y]=meshgrid(-2:1:2);t=2;Z=[(sin(t))^3 t^2 sin(t) cos(t) (sin(t))^2;t^2 sin(t) (cos(t))^4 cos(t) (sin(t))^2;t sin(t) cos(t) t^2 (sin(t))^2;sin(t) (cos(t))^3 t^2 (sin(t))^2