Verified answer

Sinπ/6*Cosx+Cosπ/6*Sinx≤1

sin(pi/6+x) ≤1

pi/6+x ≤pi/2+2pi*k

x ≤ pi/2-pi/6+2pi*k

x ≤  2pi/6+2pi*k

x ≤ pi/3+2pi*k