Hey, I have a system of ODE and I can't draw it's phase curve. I tried to use DEplot and phaseportrait, but it doesn't work. Here is my system:
dx/dt=x
dy/dt=ky (k is a constant)
Here is my piece of code:
DE := [diff(x(t), t) = x(t)];
DF := [diff(y(t), t) = k*y(t)];
with(DEtools);
phaseportrait([DE, DF], [y, x], t = -5 .. 5, y = -5 .. 5, x = -5 .. 5, k = -5 .. 5, color = black, linecolor = red);
Can anyone help me please?