计算x^2+y^2=1,1/2xy=1/8
计算3xy[2xy-x(y-2)+x-1]
计算:(-3x^2y)(1/3xy^2)=?
计算:(-3x^y)(1/3xy^2)=?
计算2分之1xy²(-2xy)+3x²y的3次方=
若x+y=1,xy=-2,计算x-y的值
计算:(5-xy/x^3-x^2y)/(1-5/xy)^2*(y-x)^3
x=2 ,y=1,计算xy分之一+(x+1)(y+1)分之一+.+(x+2010)(y+2010)的值
计算(3x^3y-x^2y+1/2xy)÷(-1/2xy)
xy/3x+2y=1/8 xy/2x+3y=1/7
数学极限计算lim(x,y)→(0,0) xy/ [√(2-e^xy)-1]= lim(x,y)→(0,0) -xy/(
已知:xy+x=-1,xy-y=-2.
计算3x[xy-2x(1/y-x/3]+3y(x²-y²)