# Math Help - A little algebraic thing I don't get in this math video

1. ## A little algebraic thing I don't get in this math video

In this video (Improper Integral with an Infinite Discontinuity in the interval), at 2:48, I don't understand how he gets -ln(2) because I would of gotten -ln|e^(-1) - 1|.

Any input would be greatly appreciated!

2. Originally Posted by s3a
In this video (Improper Integral with an Infinite Discontinuity in the interval), at 2:48, I don't understand how he gets -ln(2) because I would of gotten -ln|e^(-1) - 1|.

Any input would be greatly appreciated!
You are correct.

3. Is he also correct though?

4. Originally Posted by s3a
Is he also correct though?
I don't think so. ln(e^-x - 1) cannot be equal to ln(-x -1) at x = -1.