运用数论函数和原根与指数理论证明了:单位分数1/α=0.α1.α2…αr,α1,α2…αr,是循环部分,r是偶数;而且1/α=0.α1.α2…αr,的充要条件是α是一个奇素数,而且10是模α的原根,从而解决了有关单位分数的一个难题。
In this paper, number theory function and primitive root and Index theory were used to prove: Unit fractions ; be cycle part, be a couple number and , If and only if be a simple prime number and 10 be a primitive root mode. A puzzle concerning unit fractions has been solved.