Simplify differential equation

[lrdheat]

Thanks Han for the correction.

The TI is correct, and actually, the CASIO Classpad 400 produces Han's result with the closest fidelity...it has the same numerator, and in the denominator, has t^2 *e^t^2 - e^t^2 -2*const(1) i.e., the CASIO did not factor out e^t^2 in the denominator.