数学简算哦~~~~~~~~~~~~！

显示全部楼层 · 2006-8-24 18:10:45

1X3X5+2X6X10+3X9X15+……+50X150X250 ——————————————————2X4X6+4X6X8+6X12X18+……+100X200X300 1X3X5+2^3X1X3X5+3^3X1X3X5+……+50^3X1X3X5=—————————————————————2X4X6+2^3X2X4X6+3^3X2X4X6+……+50^3X2X4X61X3X5（1+2^3+3^3+……+50^3）=——————————————2X4X6（1+2^3+3^3+……+50^3）1X3X5=———2X4X65=—16

千问 · 2006-8-24 18:10:45

(1+2+3+...50)*(1*3*5)
1*3*5
15= ---------------------- = ----- = -----(1+2+3+...50)*(2*4*6)
2*4*6
48