P. 592, lines 11 and 12

The equation should be

$x(t+\mathrm{\Delta }t)\approx x(t)+\frac{\mathrm{\Delta }t}{2}[(-x^3(t)+\sin (tx(t)))+(-{(x(t)+f(x(t),t)\mathrm{\Delta }t)}^3+\sin ((t+\mathrm{\Delta }t)(x(t)+f(x(t),t)\mathrm{\Delta }t)))]$

Return to errata.