等差数列和的差分方程

等差数列和的差分方程等差数列a(n)-a(n-1)=dGOa(n)-a(n-1)=a(n-1)-a(n-2)Goa(n)-a(n-1)-a(n-1)+a(n-2)=0GO

{A(n)-A(n-1)}-{A(n-1)-A(n-2)}-{A(n-1)-A(n-2)}+{A(n-2)-A(n-3)}=0

Go{X*X*X-X*X}-{X*X-X}-{X*X-X}+{X-1}=0GO(X*X-2*X+1)*(X-1)=0GO(X-1)^3=0有三重根，设A(n)=A+B*n+C*n*n有方程组如下：A+B+C=a0A+2*B+4*C=a0+d+a0A+3*B+9*C=a0+d+d+a0+d+a0

solve getA ,B,C