A.a=1,b=-1/6 B.a=1,b=1/6 C.a=-1,b=-1/6 D.a=-1,b=1/6
設(shè)可微函數(shù)z=f(x,y)滿足。證明:在變換ξ=x,η=x2+y2下,上述方程可化為