Fundamental period of sinx is 2pi, for cosx it is 2pi
for sin(ax) it is 2pi/a (a is positive)
and same for cos x
so for sin(pi.x/2) it is 4/1
for cos(pi.x/3) it is 6/1
for the combination, period is [ LCM of (4,6) ]
= 12= 12
So the period of given function is 12.