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一、问题与思考题1(黄陂一中盘龙校区2018届高二上数学周练(5))如图1,在△ABC中,∠ABC sin/2=3~(1/2)/3,AB=2,点D在线段AC上,且AD=2DC,BD=4(3~(1/2))/3.(1)求BC的长;(2)求△DBC的面积.这是我校2018届高二数学周练的一道三角函数题,按常理,三角函数是我们必拿分的知识点,但是从老师讲解的情况来看,第(1)问得分率极低,是什么原因呢?我百思不得其解,
First, the problem and thinking Question 1 (Huangpi a Panlong Campus 2018 high school mathematics Zhou Lian (5)) Figure 1, △ ABC, ∠ABC sin / 2 = 3 ~ (1/2) / 3, AB = 2, point D is on line AC, and AD = 2DC, BD = 4 (3 ~ (1/2)) / 3. (1) Find the length of BC; Our school 2018 sophomore mathematics week practice a trigonometric function problem, according to common sense, the trigonometric function is the point of knowledge we must take points, but from the teacher to explain the situation, the first (1) asked scoring rate is very low, what is the reason What? I baffled,