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若(1-2x)^5=a0+a1(x-1)+a2(x-1)^2+.+a5(x-1)^5,则a1+2a2+3a3+4a4+5a5=?

题目详情
若(1-2x)^5=a0+a1(x-1)+a2(x-1)^2+.+a5(x-1)^5,
则a1+2a2+3a3+4a4+5a5=?
▼优质解答
答案和解析
(1-2x)^5=a0+a1(x-1)+a2(x-1)^2+.+a5(x-1)^5
则设f(x)=(1-2x)^5
求导数得:
f'(x)=5[(1-2x)^4]*(-2)=-10(1-2x)^4
且f'(x)=a1+2a2(x-1)+3a3(x-1)^2+4a4(x-1)^3+5a5(x-1)^4
令x=2
则:(1-2*2)^4=a1+2a2+3a3+4a4+5a5
即:a1+2a2+3a3+4a4+5a5
=(-3)^4
=81