need help solving for an unstable manifold

x'_{1}= -x_{1}

x'_{2} = -x_{2} + x^{2}_{1}

x'_{3} = x_{3} + x^{2}_{2 Using Perko's method, compute the first 3 approximations of the stable and unstable
manifolds at the steady state (0,0,0).
I can get the stable, but don't understand how to do the unstable.}http://www.cds.caltech.edu/~murray/w...Week4Notes.pdf

shows perkos method for stable but not unstable, it says to switch t for -t to do unstable, but i get infinity for x3. I don't think I should be getting that. help please!