1x2x3x4+1=5x5,2x3x4x5+1=11x11,3x4x5x6+1=19x19.第5个式子是?
观察下列各式:1x2x3x4+1=25=5^2,2x3x4x5+1=121=11^2,3x4x5x6+1=361=19^
求规律 根号1x(乘法的意思)2x3x4+1=5 根号2x3x4x5+1=11 根号3x4x5x6+1=19 根号4x5
1/1X3+1/3X5+1/5X7...1/17X19+1/19X21=
观察下列等式:1X2=1/3X1X2X3;1X2+2X3=1/3X2X3X4;1X2+2X3+3X4=1/3X3X4X5
2/1x3+2/3X5+2/5x7=2/7x9+2/9x11
1/1x3+1/3x5+1/5x7+1/7x9+1/9x11=?
裂项法1/2X5+1/5x8+1/8x11.1/2009x2012=?
这道题怎样巧算1/1x2x3x4+1/2x3x4x5+.+1/7x8x9x10
1/2x5+1/5x8+1/8x11+…………+1/2003x2006+1/2006x2009 = 这是我儿子的小学作业
已知1-1/3=2/1x3,计算1/1x3+1/3x5+1/5x7+1/7x9+1/9x11=
1/2x5+1/5x8+1/8x11+.+1/32x35
求前n项和1.1/(2X5),1/(5X8),1/(8X11)...2.2^2/(1X3),4^2/(3X5),6^2/