TM NGHI^E.M T^O'NG QUAT CU'A PHU.O.NG TRNH VI PH^AN

91)

Tm nghi^e.m t^o'ng quat cu'a phu.o.ng trnh vi ph^an:

(sinxy+xycosxy)dx+x

²

cosxydy= 0HD gia’i:

Phu.o.ng trnh vi ph^an toan ph^an co nghi^e.m t^o'ng quat la

^{xsin(xy) =C}

.