设(x+2)^9=a0+a1x+a2x^2+...+a9x^9 求(a1+3a3+5a5+7a7+9a9)^2--(2a2+4a4+6a6+8a 8)^2

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设(x+2)^9=a0+a1x+a2x^2+...+a9x^9 求(a1+3a3+5a5+7a7+9a9)^2--(2a2+4a4+6a6+8a 8)^2

设(x+2)^9=a0+a1x+a2x^2+...+a9x^9 求(a1+3a3+5a5+7a7+9a9)^2--(2a2+4a4+6a6+8a 8)^2
设(x+2)^9=a0+a1x+a2x^2+...+a9x^9 求(a1+3a3+5a5+7a7+9a9)^2--(2a2+4a4+6a6+8a 8)^2

设(x+2)^9=a0+a1x+a2x^2+...+a9x^9 求(a1+3a3+5a5+7a7+9a9)^2--(2a2+4a4+6a6+8a 8)^2
当x=1时,a0+a1+a2+a3+a4+a5+a6+a7+a8+a9=19683 ①
当x=-1时,a0-a1+a2-a3+a4-a5+a6-a7+a8-a9=1 ②
当x=0时,a0=2^9=512
①-②得:a1+a3+a5+a7+a9=9841
①+②得:a0+a2+a4+a6+a8=9842
a2+a4+a6+a8=9330
(a1+a3+a5+a7+a9)²-(a2+a4+a6+a8)²=9841²-9330²
=(9841-9330)×(9841+9330)
=9796381

(x+2)^9=a0+a1x+a2x^2+…+a9x^9
两边求导得
9(x+2)^8=a1+2a2x+3a3x^2…+9a9x^8
令x=1,
9(1+2)^8=a1+2a2+3a3…+9a9
9*3^8=a1+2a2+3a3…+9a9
3^2*3^8=a1+2a2+3a3…+9a9
3^10=a1+2a2+3a3…+9a9
a1+...

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(x+2)^9=a0+a1x+a2x^2+…+a9x^9
两边求导得
9(x+2)^8=a1+2a2x+3a3x^2…+9a9x^8
令x=1,
9(1+2)^8=a1+2a2+3a3…+9a9
9*3^8=a1+2a2+3a3…+9a9
3^2*3^8=a1+2a2+3a3…+9a9
3^10=a1+2a2+3a3…+9a9
a1+2a2+3a3…+9a9=3^10
令x=-1,
9(x+2)^8=a1+2a2x+3a3x^2…+9a9x^8
9(-1+2)^8=a1-2a2+3a3…+9a9
9*1^8=a1-2a2+3a3-4a4…+9a9
9=a1-2a2+3a3-4a4…+9a9
a1-2a2+3a3-4a4…+9a9=9
(a1+3a3+5a5+7a7+9a9)^2-(2a2+4a4+6a6+8a 8)^2
=[(a1+3a3+5a5+7a7+9a9)-(2a2+4a4+6a6+8a 8)][(a1+3a3+5a5+7a7+9a9)+(2a2+4a4+6a6+8a 8)]
=(a1+2a2+3a3…+9a9)(a1-2a2+3a3-4a4…+9a9)
=3^10*9
=3^10*3^2
=3^12

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3^12

(x+2)^9=a0+a1x+a2x^2+…+a9x^9
两边求导得
9(x+2)^8=a1+2a2x+3a3x^2…+9a9x^8
令x=1,
9(1+2)^8=a1+2a2+3a3…+9a9
9*3^8=a1+2a2+3a3…+9a9
3^2*3^8=a1+2a2+3a3…+9a9
3^10=a1+2a2+3a3…+9a9
a1+...

全部展开

(x+2)^9=a0+a1x+a2x^2+…+a9x^9
两边求导得
9(x+2)^8=a1+2a2x+3a3x^2…+9a9x^8
令x=1,
9(1+2)^8=a1+2a2+3a3…+9a9
9*3^8=a1+2a2+3a3…+9a9
3^2*3^8=a1+2a2+3a3…+9a9
3^10=a1+2a2+3a3…+9a9
a1+2a2+3a3…+9a9=3^10
令x=-1,
9(x+2)^8=a1+2a2x+3a3x^2…+9a9x^8
9(-1+2)^8=a1-2a2+3a3…+9a9
9*1^8=a1-2a2+3a3-4a4…+9a9
9=a1-2a2+3a3-4a4…+9a9
a1-2a2+3a3-4a4…+9a9=9
(a1+3a3+5a5+7a7+9a9)^2-(2a2+4a4+6a6+8a 8)^2
=[(a1+3a3+5a5+7a7+9a9)-(2a2+4a4+6a6+8a 8)][(a1+3a3+5a5+7a7+9a9)+(2a2+4a4+6a6+8a 8)]
=(a1+2a2+3a3…+9a9)(a1-2a2+3a3-4a4…+9a9)
=3^10*9
=3^10*3^2
=3^12
这个对

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