殳 =(u)^2ln v =dfrac (y)(x), =2x-3y,-|||-则 dfrac (partial z)(partial y)= ()-|||-A dfrac (y)({x)^2}[ 2ln (2x-3y)+dfrac (3y)(2x-3y)] -|||-B dfrac (y)({x)^2}[ 2ln (2x-3y)-dfrac (3y)(2x-3y)] -|||-C -dfrac (2{y)^2}({x)^2}[ dfrac (ln (2x-3y))(x)+dfrac (1)(2x-3y)] -|||-D) dfrac (2{y)^2}({x)^2}[ -dfrac (ln (2x-3y))(x)+dfrac (1)(2x-3y)]