TM TCH PH^AN T^O'NG QUAT CU'A PHU.O.NG TRNH SAU

27)

Tm tch ph^an t^o'ng quat cu'a phu.o.ng trnh sau:

^{b) y}

⁰

^{= 2xy}x

²

−y

²

.HD gia’i:

D - ^ay la phu.o.ng trnh da'ng c^ap, ta da.t

^{z = y}_z

. Khi do phu.o.ng trnh tr^en

tro.' thanh

^xz

⁰

^{= z(1 +z}

²

⁾x

. Suy ra nghi^e.m cu'a phu.o.ng trnh

1−z

²

. Hay

⁽¹1 +z

²

)dz = dxz − 2z

nay la

^z1 +z

²

=Cx, C6= 0.

V^a.y nghi^e.m cu'a phu.o.ng trnh da~ cho la

^x

²

^+y

²

^=C

¹

^{y, C}

¹

^{6= 0.}