Yet another characterization of the sine function

Robert Gervais, Lee A. Rubel
1981 International Journal of Mathematics and Mathematical Sciences  
In this expository paper, it is shown that if an entire function of exponential type vanishes at least once in the complex plane and if it has exactly the same number of zeros (counting multiplicities) as its second derivative, then this function must take the formAsin(Bz+C).
doi:10.1155/s0161171281000239 fatcat:2ykcenhecna37aq36dywumwa7m