苏教版数学必修5第45页练习中有这样一道题:某钢材库新到200根相同的圆钢,要把它们堆放成正三角形垛(每一层的根数比上一层根数多1根),并使剩余的圆钢尽可能地少,那么将剩余多少根圆钢?解设只能堆放n层,则从最上层往下,每层圆钢数组成以1为首项,1为公差的等差数列,且余下的圆钢 Su P.E. mathematics Compulsory 5 page 45 There is a question in the exercise: a new steel bar has 200 new rounds of the same steel, and they must be stacked in a regular triangular shape (the number of roots in each layer is one more than the number of layers in the upper layer). (root), and make the remaining round steel as little as possible, then the number of remaining round steel solution can only be stacked n layers, then from the top to the bottom, the number of round steel composition per layer to 1 for the first item, 1 is Tolerance of the difference series, and the remaining round steel