\[ \left \{x''(t)=\frac {k x(t)}{\left (x(t)^2+y(t)^2\right )^{3/2}},y''(t)=\frac {k y(t)}{\left (x(t)^2+y(t)^2\right )^{3/2}}\right \} \] ✗ Mathematica : cpu = 0.00787225 (sec), leaf count = 0 , could not solve
DSolve[{Derivative[2][x][t] == (k*x[t])/(x[t]^2 + y[t]^2)^(3/2), Derivative[2][y][t] == (k*y[t])/(x[t]^2 + y[t]^2)^(3/2)}, {x[t], y[t]}, t]
✗ Maple : cpu = 0. (sec), leaf count = 0 , exception
time expired