题目内容
设a>0,b>0,a,x1,x2,b成等差数列,a,y1,y2,b成等比数列,则x1+x2与y1+y2的大小关系是( )A.x1+x2≤y1+y2 B.x1+x2≥y1+y2
C.x1+x2<y1+y2 D.x1+x2>y1+y2
B
解析:(x1+x2)-(y1+y2)=a+b-(aq+aq2)=a(1+q3-q2-q)=a(1+q)(1-q)2≥0.
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题目内容
设a>0,b>0,a,x1,x2,b成等差数列,a,y1,y2,b成等比数列,则x1+x2与y1+y2的大小关系是( )A.x1+x2≤y1+y2 B.x1+x2≥y1+y2
C.x1+x2<y1+y2 D.x1+x2>y1+y2
B
解析:(x1+x2)-(y1+y2)=a+b-(aq+aq2)=a(1+q3-q2-q)=a(1+q)(1-q)2≥0.