Yes, you are both correct. Just in different forms.
You should know that
antidifferentiate sin(3x-pi/4) :using a pen and paper, I got (-1/3)cos(3x-pi/4) + c. I also tried it on ti-89 titanium and I got an answer that i think is incorrect.Here is a screen shot: so my question is, can we say the ti 89 answer is also correct?