do you graph the isoclines with a calculator? often they involve powers of e so it seems tricky to do it in your head

an interesting thing to do is to predict the behavior of the solution as t goes to infinity. the isoclines are slope lines where dy/dt=m=-a(t)y+b(t) for instance. another example of isoclines would be circles for: y'=-y/(x^2+y^2) where the circles become flattened out into the null cline m=y=0