题干

(Ⅰ)二项式 (x+
2
x
3
)
n(nN*) 的前三项的系数的和为129,写此展开式中所有有理项和二项式系数最大的项;

(Ⅱ)已知 (3x1)7=a0+a1x+a2x2++a7x7 ,求下列各式的值.

1 a0

2 a1+a2+a3+…+a7

3 a1+a3+a5+a7

4 a0+a2+a4+a6

5 |a0|+|a1|+|a2|+…+|a7|.

上一题 下一题 0.0难度 选择题 更新时间:2015-02-12 08:19:44

答案(点此获取答案解析)

解:(Ⅰ)∵二项式 (x+2x3)

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    One day, Jim played basketball in the living room after school. When he was playing in high spirits, his basketball 1 a vase off the shelf by accident and the mouth of it knocked off a large piece. What made him more2 was that the vase was rare and valuable. To cover the great 3 he caused, he glued the pieces together and put the vase back to its place.

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    “But, Mum, I ...” His mother18him and said. “My chocolate box has been 19, so our talk is over, too. Now, go to bed!” Then she left for her own bedroom. The following days were the same as before. The only 20 was that Jim never told a lie since then.

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