> dsolve({diff(y(t), t) = t^9/y(t)^3, y(1) = 9}, y(t)); (1/4) 1 (1/2) / 10 \ y(t) = - 5 \10 t + 164015/ 5 ; > dsolve({(D@@2)(y)(t) + 20*D(y)(t) + 62*y(t) = 0, y(0) = 1, D(y)(0) = 0}, y(t)); /1 5 (1/2)\ // (1/2)\ \ y(t) = |- + -- 38 | exp\\-10 + 38 / t/ \2 38 / /1 5 (1/2)\ / / (1/2)\ \ + |- - -- 38 | exp\-\10 + 38 / t/ \2 38 / ; > a1 := 55; > a2 := 62; > a3 := 22; > A := Matrix([[a1, a2, a3], [a2, a3, a1], [a3, a2, a1]]); [55 62 22] [ ] A := [62 22 55] [ ] [22 62 55] ; > with(LinearAlgebra); > evalf(Eigenvalues(A)); [&uminus0;40.] [ ] [ 33. ] [ ] [ 139. ] ; > evalf(Eigenvectors(A)); [ 33. ] [&uminus0;0.8937836515 1. 1.] [ ] [ ] [&uminus0;40.], [&uminus0;0.03768967205 &uminus0;1.887096774 1.] [ ] [ ] [ 139. ] [ 1. 1. 1.] ; # all values =0 are replaced with 1