1x2 2x3 3x4

用克拉默法则解下列方程组x1-2x2+3x3-4x4=4x2-x3+x4=-3x1+3x2+2x4=1-7x2+3x3+x4=3x1-2x2+3x3-4x4=4x2-x3+x4=-3x1+3x2+2x

解方程组X1-2x2+3x3-x4=1,3x1-x2+5x3-3x4=2,2x1+x2+2x3-2x4=3解方程组X1-2x2+3x3-x4=1,3x1-x2+5x3-3x4=2,2x1+x2+2x3

写出方程组2*x1+x2-x3+x4=1,x1+2*x2+x3-x4=2,x1+x2+2*x3+x4=3的通解?写出方程组2*x1+x2-x3+x4=1,x1+2*x2+x3-x4=2,x1+x2+2

求非齐次线方程组的通解：2x1+x2-x3+x4=1x1+2x2+x3-x4=2x1+x2+2x3+x4=3求非齐次线方程组的通解：2x1+x2-x3+x4=1x1+2x2+x3-x4=2x1+x2+

具体写出方程组：2x1+x2-x3+x4=1;x1+2x2+x3-x4=2;x1+x2+2x3+x4=3的通解具体写出方程组：2x1+x2-x3+x4=1;x1+2x2+x3-x4=2;x1+x2+2

x1+5x2-x3-x4=-1x1-2x2+x3+3x4=33x1+8x2-x3+x4=1x1+5x2-x3-x4=-1x1-2x2+x3+3x4=33x1+8x2-x3+x4=1x1+5x2-x3-

解一道方程组x1+x2+x3=5,x2+x3+x4=1,x3+x4+x5=-5,x4+x5+x1=-3,x5+x1+x2=2解一道方程组x1+x2+x3=5,x2+x3+x4=1,x3+x4+x5=-

用初等行变换来解下列线性方程组（1）2x1-x2+3x3=33x1+x2-5x3=04x1-x2+x3=3x1+3x2-13x3=-6(2)x1-2x2+x3+x4=1x1-2x2+x3-x4=-1x

1X2+2X3+3X4+.NX(N+1)1X2+2X3+3X4+.NX(N+1)1X2+2X3+3X4+.NX(N+1)n(n+1)=n²+n原式=(1+2+……+n)+(1²+2

1X2+2X3+3X4+.NX(N+1)规律1X2+2X3+3X4+.NX(N+1)规律1X2+2X3+3X4+.NX(N+1)规律这个数列的通项an=n(n+1)即an=n^2+nn(n+1)(2n

1x2+2x3+3x4+.+2011x20121x2+2x3+3x4+.+2011x2012 1x2+2x3+3x4+.+2011x2012整数裂项1/(2011×2012)×(1×2+2×

1x2+2x3+3x4+4x5+.+15x161x2+2x3+3x4+4x5+.+15x161x2+2x3+3x4+4x5+.+15x16可看成通项公式an=n×（n+1）的前15项之和,前n项和Sn

1x2+2x3+3x4+.+100x101=1x2+2x3+3x4+.+100x101=1x2+2x3+3x4+.+100x101=1x2+2x3+3x4+.+100x101=的通项公式An=n*(n

1x2+2x3+3x4+.+100x101=?结果1x2+2x3+3x4+.+100x101=?结果1x2+2x3+3x4+.+100x101=?结果x2+2x3+3x4+.+100x101=的通项公

1x1!+2x2!+3x3!+4x4!.nxn!1x1!+2x2!+3x3!+4x4!.nxn!1x1!+2x2!+3x3!+4x4!.nxn!由kxk!=(k-1+1)k!=(k+1)!-k!依次代

1X2+2x3+3x4+……+2013x20141X2+2x3+3x4+……+2013x20141X2+2x3+3x4+……+2013x2014采纳必答

1x2+2x3+3x4+.+19x201x2+2x3+3x4+.+19x201x2+2x3+3x4+.+19x20【解答】原式×3可以得到如下变形1×2×3＋2×3×3＋3×4×3＋……＋19×20×

1x2+2x3+3x4+.+999x10001x2+2x3+3x4+.+999x10001x2+2x3+3x4+.+999x1000每一项这样拆：n*(n+1)=1/3[n*(n+1)(n+2)-(n

1x2+2x3+3x4+.99x100=?1x2+2x3+3x4+.99x100=?1x2+2x3+3x4+.99x100=?1x2+2x3+3x4+…+n(n+1)=1x(1+1)+2x(2+1)+

1X2+2x3+3x4+...99x100=1X2+2x3+3x4+...99x100=1X2+2x3+3x4+...99x100=n(n+1)=(1/3){n(n+1)(n+2)-(n-1)n(n+