如图1,某学校田径场上有一旗杆OP,为了测量它的高度,在地面上选一基线AB,设其长度为d,在A点处测得P点的仰角为α,在B点处测得P点的仰角为β.
(1)若AB=20,α=30°,β=45°,且∠AOB=30°,求旗杆的高度h;
(2)经分析若干测得的数据后,发现将基线AB调整到线段AO上(如图2),α与β之差尽量大时,可以提高测量精确度,设调整后AB的距离为d,tanβ=
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103101025718317272/SYS201311031010257183172019_ST/0.png)
,旗杆的实际高度为25,试问d为何值时,β-α最大?
考点分析:
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