To construct a progression at infinity as an expansion of function in the continuous interval, a good result was achieved.

给出了一种不含导数的函数展开方法，在函数的连续区间内构造一个无穷级数作为函数的展开式。

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Gamifiers try to capture that sense of engagement by providing rapid, continuous feedback, a clear sense of progression and goals that are challenging enough to maintain interest but not so hard as to put players off.

ECONOMIST: What video-game technology can do in the real world