如图为河岸一段的示意图.一游泳者站在河岸的A点处,欲前往对岸的C点处,若河宽BC为100m,A、B相距100m,他希望尽快到达C,准备从A步行到E(E为河岸AB上的点),再从E游到C.已知此人步行速度为v,游泳速度为0.5v.
(1)设∠BEC=θ,试将此人按上述路线从A到C所需时间T表示为θ的函数,并求自变量θ的取值范围;
(2)当θ为何值时,此人从A经E游到C所需时间T最小,其最小值是多少?
考点分析:
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如图,平面PAC⊥平面ABC,点E、F、O分别为线段PA、PB、AC的中点,点G是线段CO的中点,AB=BC=AC=4,PA=PC=2
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.求证:
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已知
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,且
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∥
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.设函数y=f(x).
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,求△ABC周长的最大值.
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已知数列{a
n}满足
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(n为正整数)且a
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已知函数f(x)=
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过双曲线
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的切线,切点为E,延长FE交双曲线右支于点P,若
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,则双曲线的离心率为
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