设[(1+2x)^3]*[(1-x)^4]=a0+a1x+a2(x)^2+······+a7(x)^7
问题描述：
设[(1+2x)^3]*[(1-x)^4]=a0+a1x+a2(x)^2+······+a7(x)^7
（1)求a0,a1,a2
答
设f(x)=[(1+2x)^3]*[(1-x)^4]=a0+a1x+a2(x)^2+······+a7(x)^7f(0)=1=a0f'(x)=6(1+2x)^2(1-x)^4-4(1+2x)^3(1-x)^3=a1+2a2x+3a3x^2+······f'(0)=6-4=2=a1f''(x)=24(1+2x)(1-x)^4-48(1+2x)^2(1-x)^3+12(1+2...