求和(x+y)+(x^2+y^2)+(x^3+y^3)+……+(x^n+y^n)

求和X+1/y+x^2+1/y^2+x^n+1/y^n 求和(x+1/y)+x^2+1/y^2)+...+(x^n+1/y^n)(x,y不等于0) 急. 求和(x+1/y)+x^2+1/y^2)+...+(x^n+1/y^n)(x,y不等于0) 求和(x+y)+(x^2+y^2)+(x^3+y^3)+……+(x^n+y^n) （x+y)+(2x+1/1*2y)+(3x+1/2*3y)+.+(9x+1/8*9y) x=2 y=90求和 求和（x+1/y）+（x^2+1/y^2）+…+（x^n+1/y^n） 求和[x+(1/y)]+[x^2+(1/y^2)]+...+[x^n+(1/y^n)] (其中x≠0,x≠0,y≠1) 分组求和求和 2+(x+y)/xy+(x^2+y^2)/x2y2+(x^3+y^3)/x^3y^3+.+(x^n+y^n)/x^ny^n(xy不等于 0) x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 化简y(x+y)+(x+y)(x-y)-x^2 求和Sn=(x+1/y)+(x^2+1/y^2)+...+(x^n+1/y^n)x不等于0,1 Y不等于1 因式分解x(x+y)(x-y)-x(x+y)^2 (x+y)(x-y)-(x-y)^2如题 (x+y)(x-y)-(x-y)^2 【2(x-y)(x-y)(x-y)-8(x-y)(x-y)(x+y)+6y(x-y)(x-y)]/2(x-y)(x-y) x^2(x-y)+(y-x) x(x-y)2-(y-x)3 计算:y-x分之x+y+x-y分之y-y-x分之2x-y 【(x-y)^2+(x+y)(x-y)】除以 2x