优优班--学霸训练营 > 知识点挑题
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            • 1.

              已知函数\(y=f(x)\)满足:对任意\(a\),\(b∈R\),\(a\neq b\),都有\(af(a)+bf(b) > af(b)+bf(a)\).

              \((1)\)试证明:\(f(x)\)为\(R\)上的单调增函数.

              \((2)\)若\(x\),\(y\)为正实数且\(\dfrac{4}{x} +\dfrac{9}{y} =4\),比较\(f(x+y)\)与\(f(6)\)的大小.

            • 2.
              已知函数\(f(x)\)的定义域是\((0,+∞)\),当\(x > 1\)时\(f(x) > 0\),且\(f(xy)=f(x)+f(y)\)
              \((1)\)求证:\(f( \dfrac {1}{x})=-f(x)\)
              \((2)\)证明:\(f(x)\)在定义域上是增函数
              \((3)\)如果\(f( \dfrac {1}{3})=-1\),求满足不等式\(f(x)-f( \dfrac {1}{x-2})\geqslant 2\)的\(x\)的取值范围.
            • 3.

              定义在\(R\)上的奇函数\(f\left( x \right)\)满足条件\(f\left( 1+x \right)=f\left( 1-x \right)\),当\(x∈\left[0,1\right] \)时,\(f\left( x \right)=x\),若函数\(g\left( x \right)=\left| f\left( x \right) \right|-a{{e}^{-\left| x \right|}}\)在区间\(\left[-2018,2018\right] \)上有\(4032\)个零点,则实数\(a\)的取值范围是(    )

              A.\(\left( 0,1 \right)\)
              B.\(\left( e,{{e}^{3}} \right)\)
              C.\(\left( e,{{e}^{2}} \right)\)
              D.\(\left( 1,{{e}^{3}} \right)\)
            • 4.

              已知函数\(y{=}f(x)\)的定义域\({[-}8{,}1{]}\),则函数\(g(x){=}\dfrac{f(2x{+}1)}{x{+}2}\)的定义域是\(({  })\)

              A.\(({-∞}{,}{-}2){∪}({-}2{,}3{]}\)
              B.\({[-}8{,}{-}2){∪}({-}2{,}1{]}\)
              C.\({[-}\dfrac{9}{2}{,}{-}2){∪}({-}2{,}0{]}\)
              D.\({[-}\dfrac{9}{2}{,}{-}2{]}\)
            • 5.
              已知偶函数\(y=f(x)\)在区间\([-1,0]\)上单调递增,且满足\(f(1-x)+f(1+x)=0\),给出下列判断:
              \(①f(-3)=0\);\(②f(x)\)在\([1,2]\)上是增函数;\(③f(x)\)的图象关与直线\(x=1\)对称;\(④\)函数\(f(x)\)在\(x=2\)处取得最小值;\(⑤\)函数\(y=f(x)\)没有最大值,其中判断正确的序号是 ______
            • 6.

              函数\(f(x)\)的定义域为\(D=\{x|x\neq 0\}\),且满足对于任意\(x_{1}\),\(x_{2}∈D\),有\(f(x_{1}·x_{2})=f(x_{1})+f(x_{2}).\)

              \((1)\)求\(f(1)\)的值;

              \((2)\)判断\(f(x)\)的奇偶性并证明你的结论;

              \((3)\)如果\(f(4)=1\),\(f(x-1) < 2\),且\(f(x)\)在\((0,+∞)\)上是增函数,求\(x\)的取值范围.

            • 7. 下列函数中,满足“\(f(x+y)=f(x)f(y)\)”的单调递增函数是\((\)  \()\)
              A.\(f(x)=x\;^{ \frac {1}{2}}\)
              B.\(f(x)=x^{3}\)
              C.\(f(x)=( \dfrac {1}{2})^{x}\)
              D.\(f(x)=3^{x}\)
            • 8.

              若定义在\(R\)上的函数\(f\left(x\right) \)满足:对任意的\({x}_{1},{x}_{2}∈R \)有\(f\left({x}_{1}+{x}_{2}\right)=f\left({x}_{1}\right)+f\left({x}_{2}\right)+2, \)则下列说法一定正确的是(    )

              A.\(f\left(x\right) \)为奇函数 
              B.\(f\left(x\right) \)为偶函数 
              C.\(f\left(x\right) +2\)为奇函数
              D.\(f\left(x\right) \)\(+2\)为偶函数 
            • 9. 已知函数\(f(x)\)满足:\(f(1)=\dfrac{1}{2}\),对任意实数\(x\),\(y\)都有\(f(x+y)+f(x-y)=2f(x)f(y)\)成立,则\(f(1)+f(2)+…+f(2017)=\)(    )
              A.\(1\)            
              B.\(0\)            
              C.\(-\dfrac{1}{2}\)
              D.\(-1\)
            • 10.

              若函数\(f(x)\)的定义域为\((-2,2)\),则函数\(g(x)=f(x-1)+f(3-2x)\)的定义域为________.

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