∵a(n+1)an=a(n+1)-an∴1/an-1/a(n+1)=1 等式两边同时除以 a(n+1)an∴1/a(n+1)-1/an=-1∴数列{1/an}是以1/a1=-1为首项,-1为公差的等差数列∴1/an=-1+(n-1)*(-1)=-n∴an=-1/n
a(n+1)=an/(1-an)a1=-1a2=-1/2a3=-1/3设,an=-1/n则,a(n+1)=an/(1-an)=(-1/n)/(1+1/n)=-1/(n+1)所以an=-1/n