（-1x1/2）+(-1/2x1/3)+(-1/3x1/4)+.+(-1/2007x1/2008)+(-1/2008X1

来源：学生作业帮编辑：神马作文网作业帮分类：数学作业时间：2024/11/19 17:02:34

（-1x1/2）+(-1/2x1/3)+(-1/3x1/4)+.+(-1/2007x1/2008)+(-1/2008X1/2009)

（-1x1/2）+(-1/2x1/3)+(-1/3x1/4)+.+(-1/2007x1/2008)+(-1/2008X1/2009）
=-｛（1x1/2）+(1/2x1/3)+(1/3x1/4)+.+(1/2007x1/2008)+(1/2008X1/2009)｝
=-｛1-1/2+1/2-1/3+1/3-1/4+.+1/2007-1/2008+1/2008-1/2009}
=-(1-1/2009)
=-2008/2009
补充：1/n*1/(n+1)=1/n-1/(n+1) 例如1/2*1/3=1/2-1/3=1/6

1x1\3+2x1\4+3x1\5+.+2006x1\2008的简便算法提问:1x1/2+1/2x1/3+1/3x1/4+1/4x1/5+1/5x1/6+1/6x1/7 用简便方法 float x1,x2; x1=3/2; x2=x1/2; printf("%d%.1f",(int)x1,x2); 输 min=(4*x1^2+2*x2^2+4*x1*x2+2*x2+1)*exp(x1); 求非齐次线性方程组：2x1-x2+4x3-3x4=-4;x1+x3-x4=-3;3x1+x2+x3=1;7x1+7x3- 已知方程3x²-4x=-1的两根是x1 x2,不解方程,求：1.x2/x1 + x1/x2 2.（x1 - 2 1.1x1.1x1.1-1.1x1.1-0.11 简算1.1x1.1x1.1-1.1x1.1-0.11! X2/X1(X1+X2)+X3/(X1+X2)(X1+X2+X3)+.Xn/（x1+x2+...Xn-1)(X1+X2. x1/(1+x1^2)+x2/(1+x1^2+x2^2)+.+xn/(1+x1^2+x2^2+.+xn^2) 设x1,x2,...,xn为任意实数,求证：x1/(1+x1^2)+x2/(1+x1^2+x2^2)+...+xn/(1 线性方程组线性方程组1x1+x2 -2x4=-64x1-x2-x3-x4=13x1-x2-x3 =3方程组2X1+MX