Module 2: Single Step Methods
  Lecture 5: Convergence of Euler's Method
 

 

The last term can be treated by the Mean value theorem to get a bound

where , which exists because of the continuity of and in a closed region. The treatment of the first term in (2.7) depends on our hypothesis. If we are prepared to assume that also satisfies a Lipschitz condition in t (as will happen in practice), we can bound the first term in (2.7) by where is the Lipschitz constant for as a function of . Consequently,

and so from (2.6), we get

(2.8)

Thus the numerical solution converges as .