OK, I can't figure this improper integral out -- I keep getting -ln2 and the answer is supposed to be ln2; integrate from -1 to infinity dx/(x^2+5x+6); I've tried partial fractions -- but that doesn't seem to work because I get 1/(x+2) + 0/(x+3) . . . and I can't do anything with that! Help!

Question

OK, I can't figure this improper integral out -- I keep getting -ln2 and the answer is supposed to be ln2; integrate from -1 to infinity dx/(x^2+5x+6); I've tried partial fractions -- but that doesn't seem to work because I get 1/(x+2) + 0/(x+3) . . . and I can't do anything with that!  Help!

anonymous · Answer

For the partial fractions, did you get 
1=A(x+2)+B(x+3). This works out.

anonymous · Answer

Well, I'll try again . . . I know I'm tired . . . so I'll try again!

anonymous · Answer

SO . . . this time I got 1/(x+2) and -1/(x+3) . . . ??  that would mean that 1/(x^2+5x+6) = 1/((x+2) -1/((x+3)  . . . am I on the right track?

anonymous · Answer

Thanks for your help . . . I'll keep working.  Have a good evening.

anonymous · Answer

Thats what i got for the decomposition. Good luck