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Suppose we want to minimize the function:

(4) |

Standard calculus: if we want to minimize *y*(*x*), we consider a
*small deviation:*

In this situation we have a *functional* that
depends on the *function* *M*(*x*). Same idea: consider a
deviation:

We have: Expansion: and Second term: integrating by parts: Result: This is possible only if

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© 1997

Thu Oct 16 20:58:44 EDT 1997