5X/1*2+5X/2*3+……5X/2004*2005
1x+2x+3x+4x+5x+6x+7x…+99x=100
x+2/x+1-x+3/x+2-x+4/x+3+x+5/x+4
x^5+x^4 = (x^3-x)(x^2+x+1)+x^2+x
若x+x^2+x^3+x^4=0.求x^5+x^6+…+x^2004的值
|X-1|+|X-2|+|X-3|+|X-4|+|X-5|+|X-6|+|X-7|+|X-8|+|X-9|+|X-10|
解方程x/(x-2)=2x/(x-3)+(1-x)/(x-5x+6)
5x(3x-2)-(x+1)
求和:Sn=1+3x+5x*x+7x*x*x+……+(2n-1)x^n-1 (x不为0和1)
x/x-3-5x/x^2-x-6计算
(X-1)^3(x-2)(x-3)^2(x-5)
1/(x+3)-(x-2)/(x^2-5x+6)
(2x-1)/(x-1)(x-2)=(x-5)/(x-2)(x-3) x/2x^2-11x-21=(x+7)/x^2-1