Arcsin0-arcsin(-√3/2)=0+π/3=π/3
arccos(-√3/2)+arccos(-√2/2)=π-π/3+π-π/4=2π-7π/12=17π/12
arcsin1-2arccos(-√2/2)=π/2+π-π/4=5π/4
2arctg(-√3)+arccos(-√3/2)+arcsin1=-2π/3+π-π/6+π/2=2π/3
arcsin0+arctg0=0+0=0
arcsin(-√2/2)+arccos 1/2=-π/4+π/3=π/12
arccos(cos(-6π/5))=arccos(cos(6π/5))=arccos(-cosπ/5)=π-π/5=π/4
6π/5=π+π/5, cos(π+π/5)=-cosπ/5
arcsin(cosπ/9)=arcsin(sin7π/18)=7π/18
cosπ/9= sin (π/2-π/9)=sin (7π/18)
tg(arctg3/8)=3/8
ctg(arcctg(-5/4))=ctg(π-arcctg5/4)=-ctg(arcctg(5/4))=-5/4