We save the definition: f(x) = 2·sin(π2·x) Let's find the smallest positive period of 2·sin(π2·x) The period of sin(x) is 2π; for a·sin(bx + c) + d, we obtain T = 2·πabs(b). The nonzero factor a and the shifts c and d do not change the period. The coefficient of x in πx2 is π2 T = 2ππ2 T = 2π·2π T = 4ππ T = 4 ▶Period: 4