定义1*4=1x2x3x4 2*3=2x3x4 求6*3 5*4
1/1X2+2/1X2X3+3/1X2X3X4+4/1X2X
如果定义(3)=2x3x4,(5)=4x5x6,(9)=8x9x10,那么(4)+(6)是多少?
1/1x2x3+1/2x3x4+1/3x4x5+1/4x5x6+.+1/48x49x50=
请1/1x2x3+1/2x3x4+1/3x4x5+1/4x5x6=
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
1/1x2x3+1/2x3x4+1/3x4x5
1x2X3+2x3X4+3x4X5+…+7X8X9=?
1x2x3+2x3x4+3x4x5+…+8x9x10
1x2x3+2x3x4+3x4x5+...+7x8x9=,
1x2x3+2x3x4+3x4x5+.+10x11x12