材料一:在加压的情况下,25m3的石油气可装人容积为0.024m3的钢瓶中,说明:____.
材料二:敞口容器中的酒精逐渐减少,说明:____.
(Ⅰ)设函数f(x)=|x﹣1a|+|x+a|(a>0).证明:f(x)≥2;
(Ⅱ)若实数x,y,z满足x2+4y2+z2=3,求证:|x+2y+z|≤3.
Sometimes, there is only one step between failure and s____.