Ask a question about periodic function F (x) is a bounded function on R, f (x + 13 / 42) + F (x) = f (x + 1 / 6) + F (x + 1 / 7), find the smaller positive period of F (x) The answer in the reference book is 1 / 42, but the process is wrong. I can only prove that 1 is the period of F (x) How to find out that 1 / 42 is f (x) period,

Ask a question about periodic function F (x) is a bounded function on R, f (x + 13 / 42) + F (x) = f (x + 1 / 6) + F (x + 1 / 7), find the smaller positive period of F (x) The answer in the reference book is 1 / 42, but the process is wrong. I can only prove that 1 is the period of F (x) How to find out that 1 / 42 is f (x) period,

Let K / 42 = se ^ (i13s) + e ^ (i42s) - e ^ (i6s) - e ^ (i7s) = 0e ^ (i7s) + e ^ (i36s) - 1-e ^ (is) = 0 (e ^ (i6s) - 1) {e ^ (i30s) + e ^ (i24s) + e ^ (i18s)