4)
sinx<(-</span>√2/2)
a2=arcsin(-√2/2)=7p/4
a1=3p/2-p/4=5p/4
a2>a1
7p/4+2pn>x>5p/4+2pn
(7p/4+2pn; 5p/4+2pn)
5)
cosx=>√2/2
a1=arccos√2/2=p/4
a2=p/2
a2>a1
[p/4+2pn; p/2+2pn]
6)
ctgx<=</span>√3
a1=acrctg0=p/2+pn a3=p+pn
a2=p/6 a4=p+p/6=7p/6+pn
[p/2+pn;p/6]U[p+pn; 7p/6+pn]