①当x>2时,y随x的增大而减小;
②若图象经过点(0,1),则﹣1<a<0;
③若(﹣2021,y1),(2021,y2)是函数图象上的两点,则y1<y2;
④若图象上两点( , y1),(+n,y2)对一切正数n,总有y1>y2 , 则1<m≤ .