The expression f ( x ( t ) + c 2 f ( x ( t ) , t ) Δ t , t + c 4 Δ t ) {\displaystyle f\left(x(t)+c_{2}f(x(t),t)\Delta t,t+c_{4}\Delta t\right)} should be
f ( x ( t ) + c 3 f ( x ( t ) , t ) Δ t , t + c 4 Δ t ) {\displaystyle f\left(x(t)+c_{3}f(x(t),t)\Delta t,t+c_{4}\Delta t\right)}
Return to errata.