Module 6: Implicit Runge-Kutta Methods
  Lecture 16: Derivation of Implicit Runge-Kutta methods
 

 

Now from (6.2) with , we have

,

Expanding by Taylor series about we get

(6.5)

Since these two equations are implicit, we can no longer proceed by successive substitution as done in the case of explicit Runge-Kutta methods earlier. Let us assume instead, that the solutions for and may be expressed in the form

(6.6)

Substituting for by (6.6) in (6.5) we get