P. 167, lines -4,-3 and -2

The derivatives should be:

$\frac{df}{dt}(t)=-\frac{2t}{(1+t^2{)}^2}$

$\frac{d^{2}f}{d{t}^2}(t)=\frac{6t^2}{(1+t^2{)}^3}-\frac{2}{(1+t^2{)}^3}$

$\frac{d^{3}f}{d{t}^3}(t)=-\frac{24t^3}{(1+t^2{)}^4}+\frac{24t}{(1+t^2{)}^4}$

Return to errata.