数列{an}中a1=4,a(n+1)=an/2+2/an(I)设bn=lg((an+2)/(an-2)),求证bn等比数列(II)求an
数列{an}中a1=4,a(n+1)=an/2+2/an(I)设bn=lg((an+2)/(an-2)),求证bn等比数列(II)求an
数学人气:364 ℃时间:2019-11-04 16:52:20
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1.a(n+1)=an/2 +2/an=(an²+4)/(2an)a(n+1)+2=(an²+4an+4)/(2an)=(an +2)²/(2an) (1)a(n+1)-2=(an²-4an+4)/(2an)=(an-2)²/(2an) (2)(1)/(2)[a(n+1)+2]/[a(n+1)-2]=[(an +2)/(an -2)]²l...
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