2∂∂∂∂∂∂XYXYXY∂ + 7∂ + 3∂ = 0 ∂ - 4∂ + 222UU2UUU

2. - BAI TAP CHO 16 UNIT 12 CO DAP AN
BAI TAP CHO 16 UNIT 12 CO DAP AN
2.

2

∂xy∂ + 7∂ + 3∂ = 0 ∂ - 4∂ +

2

2

u

2

u