f(0)=2,,,,say the function has a period T then f(T)=2 so at that poit T both Cos T=1 and Cos (sqrt{2}T)=1 the first gives T=2mpi for some integre m and the second gives sqrt{2}T=2npi for soe integer n which is a contradiction unless both m=n=0 ...so the function can't be periodic
Moderation Team
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