1, cho \(M=\dfrac{1}{2-\sqrt{3}}\) và \(N=\sqrt{6}.\sqrt{2}\) kết quả của phét tính 2M - N bằng
a, \(4+4\sqrt{3}\) b, \(2+\sqrt{3}\) c,4 d, \(2\sqrt{3}\)
2, với x>6 thì biểu thức \(-x+\sqrt{\left(6-x\right)^2}\) rút gọn đc kết quả bằng
a, -2x+6 b,2x-6 c -6 d, 6
3, cho hàm số y=f(x)=\(\dfrac{1}{3}\) x -1 khẳng định nào sao đây đúng
a, f(2)<f(3) b, f(-3)< f(-4) c, f (-4)>f(2) d, f(2)<(0)
4,cho tam giác ABC đều cạch a nội tiếp đg tròn (O;R) giá trị của R bằng
a, \(R=\dfrac{a\sqrt{3}}{3}\) b, R=a c, \(R=a\sqrt{3}\) d, \(R=\dfrac{a\sqrt{3}}{2}\)
1. \(2M-N=\dfrac{2}{2-\sqrt{3}}-\sqrt{6}.\sqrt{2}=\dfrac{2-2\sqrt{3}\left(2-\sqrt{3}\right)}{2-\sqrt{3}}=\)\(\dfrac{2-4\sqrt{3}+6}{2-\sqrt{3}}=\dfrac{8-4\sqrt{3}}{2-\sqrt{3}}=4\)
Đáp án C
2. Ta có: A= \(-x+\sqrt{\left(6-x\right)^2}=-x+\left|6-x\right|\)
Mà x>6 \(\Rightarrow6-x< 0\)A=-x-6+x=-6
Đáp án C
3. Vẽ đồ thị hàm f(x) ta có:
Ta thấy f(2)<f(3), chọn Đáp án A
4.![](data:image/png;base64,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)
Khi đó, bán kính của đường tròn bằng \(\dfrac{2}{3}\)đường cao của tam giác đều ABC
Ta có: \(R=\dfrac{2}{3}.\dfrac{a\sqrt{3}}{2}=\dfrac{a\sqrt{3}}{3}\)
Đáp án A
Câu 1: C
Câu 2: C
Câu 3: A
Câu 4: A