(2x²-x-1)³=a+a1x+a2x²+a3x³+a4x^4+a5x^5+a6x^6 则a1+a3+a5=?急
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![(2x²-x-1)³=a+a1x+a2x²+a3x³+a4x^4+a5x^5+a6x^6 则a1+a3+a5=?急](/uploads/image/z/13573002-66-2.jpg?t=%EF%BC%882x%26%23178%3B-x-1%EF%BC%89%26%23179%3B%3Da%2Ba1x%2Ba2x%26%23178%3B%2Ba3x%26%23179%3B%2Ba4x%5E4%2Ba5x%5E5%2Ba6x%5E6+%E5%88%99a1%2Ba3%2Ba5%3D%3F%E6%80%A5)
(2x²-x-1)³=a+a1x+a2x²+a3x³+a4x^4+a5x^5+a6x^6 则a1+a3+a5=?急
(2x²-x-1)³=a+a1x+a2x²+a3x³+a4x^4+a5x^5+a6x^6 则a1+a3+a5=?急
(2x²-x-1)³=a+a1x+a2x²+a3x³+a4x^4+a5x^5+a6x^6 则a1+a3+a5=?急
(2x2-x-1)3=a0+a1x+a2x2+a3x3+a4x4+a5x5+a6x6
设x=0时
-1=a0
设x=1时
(2*1*1-1-1)3=a0+a1+a2+a3+a4+a5+a6=0 1
设x=-1时
(2*(-1)*(-1)+1-1)3=a0-a1+a2-a3+a4-a5+a6=8 2
1式+2式得
2(a0+a2+a4+a6)=8
a2+a4+a6=8/2-a0=4+1=5 3
3式代入1式得
a0+a1+a3+a5=-(a2+a4+a6)=-5
a1+a3+a5=-5-a0=-5+1=-4