I solved an integral using trig sub
the answer I got was
I checked my answer on wolfram it gave
I understand the 3 and sqrt{x^2-9}. My problems is, shouldn't it be ?
Wow, I'm having the exact same problem. I posted this last night:
Simple Trig substitution; find my error
I'll follow your post and you can follow mine. Maybe we'll double our chances of getting the correction.