Incorrect formula in 3.6.3

[bwehlin]

Hi,

Thank you for providing this resource!

There is a small issue with the formula for the recurrence on page 177, Section 3.6.3 Unstable algorithms. In order for the recurrence to be correct, I believe the denominator should be changed to x+5 instead of x-5.

There's also a small typo in the error derivation, where it says "n_{n-1}" instead of "y_{n-1}".