研究了在Caputo分数阶导数下的分数阶Pfaff-Birkhoff变分问题.首先给出了Caputo分数阶导数的定义,以及相应的分部积分公式和交换关系,其次建立了分数阶Pfaff-Birkhoff原理和分数阶Birkhoff方程,最后举例说明结果的应用.
The fractional Pfaff-Birkhoff variational problem is studied under Caputo fractional derivative. First, the definition of Caputo fractional derivatives, the formula for integration by parts and the commutative relations between differential operation and variational operation are given. Second, the fractional Pfaff-Birkboff principle and the fractional Birkhoff' s equations are obtained. And finally an example is given to illustrate the application of the results.