已知{an},{bn}满足lim(2an+bn)=1,lim(an-2bn)=1,求lim(anbn)的值guocheng!
问题描述:
已知{an},{bn}满足lim(2an+bn)=1,lim(an-2bn)=1,求lim(anbn)的值
guocheng!
答
lim(2an+bn)=2lim(an)+lim(bn)=1
lim(an-2bn)=lim(an)-2lim(bn)=1
lim(an)=3/5
lim(bn)=-1/5
lim(anbn)=lim(an)*lim(bn)=3/5*(-1/5)=-3/25