Начиркал, просто отвлекся и ошибся. Надеюсь, разберешься!
<span>1)arcsin 0 =0
2)arccos 1= 0 ;
3)arcsin√2/2 =π/4 ;
4)arccos 3 не существует угол косинус </span><span>которой =3 </span><span>;
5)arcsin (-1) = -π/2 ;
6)arccos(-√3/2) = π -π/6 = 5π/6 ;
</span><span>7)arctg 0 = 0 ;
8)arctg 1 =π/4 ;
9)arctg(-√3) = - π/3 ;
10)arcctg(-√3/3) = </span><span><span>π -π/3= 2π/3 </span> ;
11)arcsin(-1/2)+arccos 1 = -π/6 +0 = -π/6 ;
12) (arcsin -1)/2+ arccos 1 = -π/4+0= -π/4;
13)cos ( arccos 1) =1;
14)sin(arcsin√2/2) =</span><span>√2/2;
15)arcsin (sin π/4) =arcsin(</span><span>√2/2) </span>=<span>π/4 ;
16)arccos ( cos(-</span><span>π/4))=</span><span>arccos ( cos(π/4))=</span><span><span>arccos (√2/2<span>))=π/4 ;
</span></span> 17)cos (arcsin(-1/3))=cos(arccos(√8/3)=</span><span><span><span>√8/3 </span>=2√2/3 ;
18)tg(arccos(-1/4)) =tq(arctq(-√15) = - √15; 1+tq²α= 1/cos²α
19)sin(arcctg(-2)) =sin(arcsin(1/√5)=1/√5 ;
20) arcsin(cos π/9)</span> =arcsin(sin(π/2 - π/9))=arcsin(sin7π/18) =</span><span><span>7π/18</span>.
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3 целых 6/10(три целых шесть десятых)