∂ A  ∂ w p    = ∑ i = 1  t  ∂ f i p    ∂ w p     f i k   ( w 3 k − 2   , w 3 k − 1   , w 3 k   )           ( 8 )    MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacH8akY=wiFfYdH8Gipec8Eeeu0xXdbba9frFj0=OqFfea0dXdd9vqai=hGuQ8kuc9pgc9s8qqaq=dirpe0xb9q8qiLsFr0=vr0=vr0dc8meaabaqaciaacaGaaeqabaqabeGadaaakeaadaWcaaqaaiabgkGi2kabdgeabbqaaiabgkGi2kabdEha3naaBaaaleaacqWGWbaCaeqaaaaakiabg2da9maaqahabaWaaSaaaeaadaWcaaqaaiabgkGi2kabdAgaMnaaBaaaleaacqWGPbqAcqWGWbaCaeqaaaGcbaGaeyOaIyRaem4DaC3aaSbaaSqaaiabdchaWbqabaaaaaGcbaGaemOzay2aaSbaaSqaaiabdMgaPjabdUgaRbqabaGccqGGOaakcqWG3bWDdaWgaaWcbaGaeG4mamJaem4AaSMaeyOeI0IaeGOmaidabeaakiabcYcaSiabdEha3naaBaaaleaacqaIZaWmcqWGRbWAcqGHsislcqaIXaqmaeqaaOGaeiilaWIaem4DaC3aaSbaaSqaaiabiodaZiabdUgaRbqabaGccqGGPaqkaaaaleaacqWGPbqAcqGH9aqpcqaIXaqmaeaacqWG0baDa0GaeyyeIuoakiaaxMaacaWLjaWaaeWaaeaacqaI4aaoaiaawIcacaGLPaaaaaa@614C@