0●(–π/2+πn; π/2+π/n) n*Z
0●(π/4+πn) |sinx+cosx=0|
0●π/4+πn |sinx–cosx=0|
0●π/2+2πn<x<3π/2+2πn,n*Z |cosx<0|
0●2<x<π+2πn |cosx>0|
0●2πn<x<π+2πn,n*Z |sinx>0|
0●πk/2, k*Z |sinx·cosx=0|
0●2πk+π/2<x<5π/2+2πk |sinx–cosx>0|
0●0 |√x+√–x=0|