I wish you and your family have a very happy and safe holiday
I happen to find out some bugs in the Ti-89 series.
The answers were wrong.
Incorrect integration from Ti-89 T, the Casio Classpad and HP 50g get the right answer:
Here is another bug list
I contacted Ti but they don't seem to interested in the Ti-89 T any more... they are not focusing on the Ti-nspire... which is sad. If they don't care about the Ti line any more... I will leave Ti and buy Casio or HP products in the future.