计算：(1) x+2y+(4y^2/x-2y

计算:1/(x-y)-1/(x+y)-2y/(x^2+y^2)-4y^3/(x^4+y^4)-8x^7/(x^8+y^8 计算(x-2y)^2-4(2x+y)(y-2x)+4x(y-2) 计算【3(x-y)^2(x+y)^-2/4(x+y)^2(x-y)^-2】^-2 计算:(-x-2y) * (3x-y) 计算（2x-3y)(x+4y)-(3x+y)(x-2y) (x-3y)(y+2x)-(4y-3x)(3x+4y)计算 计算:(x-y)^2*(y-x)^2*(x-y)^6 计算(x+y)(x+y)^2(-x-y)^3 计算:(x-2y)(1+x+2y+4y^2+2xy+x^2) 计算(4x^2-2x^3+6x)/(-2x)-(x-1)^2y^2-4/y^2-y-6)+(y+2/y-3)/(y+1/ 计算(x^8-x^7y+x^5y^3-x^4y^4+x^3y^5-x^y^7+y^8)(x^2+xy+y^2) 计算:[(2x - 3y)^2 - (x-y)(4x+2y)] / 2y