下列各函数中,最小值为2的是()A,y=x+x分之一,B,y=sinx+sinx分分之一,x属于（0

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A的值域是(-∞,-2]∪[2,+∞)
B 0＜x＜π/2
0＜sinx＜1
所以值域是(2,+∞)
C y=(x^2+3)/√(x^2+2)=√(x^2+2)+1/√(x^2+2)
因为√(x^2+2)≥√2
所以值域是[3√2/2,+∞)
D y=x+2/√x-1=x+1/√x+1/√x-1≥3[x*(1/√x)*(1/√x)]^(1/3)-1=2
所以答案应该选D才对.
======以下答案可供参考======
供参考答案1:
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供参考答案2:
你用排除法 吧。
其他貌似都有可能=0
如果有=0 最小值就不是2
B。有说了个区间。。
所以不一样。