已知1※3=1x2x3,4※5=4x5x6x7x8,请计算(6※4)/(3※4)
请1/1x2x3+1/2x3x4+1/3x4x5+1/4x5x6=
1/1x2x3+1/2x3x4+1/3x4x5+1/4x5x6+.+1/48x49x50=
1x2x3+2x3x4+3x4x5+4x5x6+...+n(n+1)(n+2)=
1/1x2x3+1/2x3x4+1/3x4x5+1/4x5x6+1/5x6x7=?这类题
1x2x3=6 3x4x5=60 5x6x7=210 2x3x4=24 4x5x6=120三个连续自然数(0除外)的乘积
1/1X2+2/1X2X3+3/1X2X3X4+4/1X2X
1x2X3+2x3X4+3x4X5+…+7X8X9=?
1x2x3+2x3x4+3x4x5+...+7x8x9=,
数学简便计算1/1x2x3+1/2x3x4+1/3x4x5……+1/20x21x22=?
max=ax1*x1+x2x3+x2*x4 {x1+x2+x3+x4=10 xi>=0,i=1,2,3,4 a为实数}利
1、求一个正交变换,将二次型f(x1,x2,x3)=2x12+3x22+3x32+4x2x3化成标准形.
1/1x2x3+1/2x3x4+1/3x4x5+1/4x5x6+...+1/8x9x10 等于多少?