定义在R上的偶函数f(x)满足:对任意的x1,x2∈【0,﹢∞)(x1≠x2),有f(x2)-f(x1)/x2-x1<0

1个回答

  • :∵(x2-x1)(f(x2)-f(x1))>0,

    ∴f(x2)-f(x1)x2-x1>则f(x)在x1,x2∈[0,+∞)(x1≠x2)上单调递增,

    又f(x)是偶函数,故f(x)在x1,x2∈(-∞,0](x1≠x2)单调递减.

    且满足n∈N*时,f(-2)=f(2),3>2>1>0,

    得f(1)<f(-2)<f(3),

    故选B.