算式 找规律1×2+2×3+···+n(n+1)=?观察下面3个等式:1×2=1/3(1×2×3-0×1×2)2×3=1/3(2×3×4-1×2×3)3×4=1/3(3×4×5-2×3×4)将这三个等式的两边相加,可以得到1×2+2×3+3×4=1/3×3×4×5=20读完这段材料,请你思
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![算式 找规律1×2+2×3+···+n(n+1)=?观察下面3个等式:1×2=1/3(1×2×3-0×1×2)2×3=1/3(2×3×4-1×2×3)3×4=1/3(3×4×5-2×3×4)将这三个等式的两边相加,可以得到1×2+2×3+3×4=1/3×3×4×5=20读完这段材料,请你思](/uploads/image/z/641300-68-0.jpg?t=%E7%AE%97%E5%BC%8F+%E6%89%BE%E8%A7%84%E5%BE%8B1%C3%972%2B2%C3%973%2B%C2%B7%C2%B7%C2%B7%2Bn%EF%BC%88n%2B1%EF%BC%89%3D%3F%E8%A7%82%E5%AF%9F%E4%B8%8B%E9%9D%A23%E4%B8%AA%E7%AD%89%E5%BC%8F%EF%BC%9A1%C3%972%3D1%2F3%281%C3%972%C3%973-0%C3%971%C3%972%292%C3%973%3D1%2F3%282%C3%973%C3%974-1%C3%972%C3%973%293%C3%974%3D1%2F3%283%C3%974%C3%975-2%C3%973%C3%974%29%E5%B0%86%E8%BF%99%E4%B8%89%E4%B8%AA%E7%AD%89%E5%BC%8F%E7%9A%84%E4%B8%A4%E8%BE%B9%E7%9B%B8%E5%8A%A0%2C%E5%8F%AF%E4%BB%A5%E5%BE%97%E5%88%B01%C3%972%2B2%C3%973%2B3%C3%974%3D1%2F3%C3%973%C3%974%C3%975%3D20%E8%AF%BB%E5%AE%8C%E8%BF%99%E6%AE%B5%E6%9D%90%E6%96%99%2C%E8%AF%B7%E4%BD%A0%E6%80%9D)
算式 找规律1×2+2×3+···+n(n+1)=?观察下面3个等式:1×2=1/3(1×2×3-0×1×2)2×3=1/3(2×3×4-1×2×3)3×4=1/3(3×4×5-2×3×4)将这三个等式的两边相加,可以得到1×2+2×3+3×4=1/3×3×4×5=20读完这段材料,请你思
算式 找规律
1×2+2×3+···+n(n+1)=?
观察下面3个等式:
1×2=1/3(1×2×3-0×1×2)
2×3=1/3(2×3×4-1×2×3)
3×4=1/3(3×4×5-2×3×4)
将这三个等式的两边相加,可以得到1×2+2×3+3×4=1/3×3×4×5=20
读完这段材料,请你思考后回答:
(1)1×2+2×3+···+9×10=____________________________
(2)1×2×3+2×3×4+···+9×10×11=_____________________________
(3)1×2×3+2×3×4+···+n×(n+1)×(n+2)=_______________________
横线上要有两部 一个结果
例:1×2+2×3+3×4=( 1/3×3×4×5=20 )
括号里是横线上填的格式
算式 找规律1×2+2×3+···+n(n+1)=?观察下面3个等式:1×2=1/3(1×2×3-0×1×2)2×3=1/3(2×3×4-1×2×3)3×4=1/3(3×4×5-2×3×4)将这三个等式的两边相加,可以得到1×2+2×3+3×4=1/3×3×4×5=20读完这段材料,请你思
(1)1/3×9×10×11=330
(2)1/4×9×10×11×12=2970
(3)1/4×n×(n+1)×(n+2)×(n+3)