若(a-14x)10=a0+a1x+a2x2+…+a10x10,其中a2a3=34;(1)求实数a的值;(2)求(a0+22a2+24a4+…+210a10)2-(2a1+23a3+25a5+…+29

题目简介

若(a-14x)10=a0+a1x+a2x2+…+a10x10,其中a2a3=34;(1)求实数a的值;(2)求(a0+22a2+24a4+…+210a10)2-(2a1+23a3+25a5+…+29

题目详情

若(a-
1
4
x
10=a0+a1x+a2x2+…+a10x10,其中
a2
a3
=
3
4

(1)求实数a的值;
(2)求(a0+22a2+24a4+…+210a102-(2a1+23a3+25a5+…+29a92的值.
题型:解答题难度:中档来源:不详

答案

(1)∵二项展开式的通项公式为ar=Tr+1=
Cr10
a10-r(-class="stub"1
4
x)r

a2
a3
=
C210
a8(-class="stub"1
4
)
2
C310
a7(-class="stub"1
4
)
3
=-class="stub"3
2
a=-class="stub"3
4

a=class="stub"1
2

(2)令x=2,得:a0+2a1+22a2+23a3+…+210a10=0
令x=-2,得:a0-2a1+22a2-23a3+…+210a10=1
A0=a0+22a2+…+210a10A1=a1+23a3+…+29a9
则A0+A1=0,A0-A1=1,
A20
-
A21
=(A0+A1)(A0-A1)=0

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