# On the Sum of Differentiable Functions

@inproceedings{Croft1962OnTS, title={On the Sum of Differentiable Functions}, author={H. T. Croft}, year={1962} }

Ryll-Nardzewski has proposed the following problem ( New Scottish Book , no. 119). If f n (x) are continuous, differentiable* functions in a closed finite interval, do there always exist constants c n (no c n = 0) (depending on the ), such that converges and is also a continuous differentiable function?