A:50的标注
B:15的标注
C:R10的标注
D:φ60的标注
已知f(x)是定义在R上的单调递增函数,则下列四个命题:
①若f(x0)>x0,则ff(x0)>x0;
②若ff(x0)>x0,则f(x0)>x0;
③若f(x)是奇函数,则ff(x)也是奇函数;
④若f(x)是奇函数,则f(x1)+f(x2)=0⇔x1+x2=0,其中正确的有( )
—How do you spend the coming May Day holiday?— I haven't decided. I wonder during the holiday.