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一、选择题1.若α,β∈(0,π/2),cos(α-β/2)=3~(1/2)/2,sin(α/2-β)=-1/2,则cos(α+β)的值等于() A)-3~(1/2)/2.(B)-1/2.(C)1/2.(D)3~(1/2)/2.2.如果复数(m~2+i)(1+mi)是实数,则实数m=() (A)1.(B)-1.(C)2~(1/2).(D)-2~(1/2).3.已知向量OA~→:(1,-3),OB= (2,-1),OC=(m+1,m-2).若点A、B、C能构成三角形,这实数m应满足的条件是() (A)m≠-2.(B)m≠1/2.(C)m≠1.(D)m≠-1.4.设有三个函数,记第一个为y=f(x),它的反函数就是第二个函数,而第三个函数的图象与第二个函数关于直线y=-x对称,则第三个函数是()
1. Multiple choice questions 1. If α, β∈(0, π/2), cos(α-β/2)=3~(1/2)/2, sin(α/2-β)=-1/ 2, then the value of cos(α+β) is equal to () A)-3~(1/2)/2.(B)-1/2.(C)1/2.(D)3~(1/ 2)/2.2. If the complex number (m~2+i)(1+mi) is a real number, then the real number m=() (A)1.(B)-1.(C)2~(1/2). (D)-2~(1/2).3. Known vector OA~→:(1,-3), OB=(2,-1), OC=(m+1,m-2). The points A, B, and C can form a triangle. The condition that the real number m should satisfy is () (A)m≠-2. (B)m≠1/2. (C)m≠1. (D)m≠- 1.4. There are three functions, the first one is y=f(x), and the inverse function is the second function. The image of the third function is symmetrical to the second function with respect to the straight line y=-x. Then the third function is ()