Question Number 30513 by Penguin last updated on 22/Feb/18
Commented by Penguin last updated on 22/Feb/18
$${f}\left({x}\right)=\mathrm{sin}\left(\lfloor{x}\rfloor\right)\left(−\mathrm{1}\right)^{\lfloor{x}\rfloor} \\ $$$$\mathrm{or},\:\boldsymbol{{similarly}}: \\ $$$${f}\left({x}\right)=\mathrm{sin}\left({x}\right)\left(−\mathrm{1}\right)^{{x}} ,\:{x}\in\mathbb{Z}\: \\ $$$$\: \\ $$$$\mathrm{The}\:\mathrm{plot}\:\mathrm{of}\:{f}\left({x}\right)\:\mathrm{seems}\:\mathrm{to}\:\mathrm{be}\:\mathrm{of}\:\mathrm{3}\:\mathrm{out}-\mathrm{of}-\mathrm{phase} \\ $$$$\mathrm{sine}-\mathrm{like}\:\mathrm{waves},\:\mathrm{with}\:\mathrm{wavelengths}\:\mathrm{of} \\ $$$$\mathrm{approximately}\:\mathrm{67}.\:\mathrm{Why}? \\ $$