3x -(π/4)=(-1)^(k)arcsin(sqrt(3))/2)+π*k, k ∈ Z
3x -(π/4)=(-1)^(k)(π/3)+π*k, k ∈ Z
3x =(-1)^(k)(π/3)+(π/4)+π*k, k ∈ Z
[b]x =(-1)^(k)(π/9)+(π/12)+(π/3)*k, k ∈ Z[/b]
можно и лучше так:
3x -(π/4)=(π/3)+2π*k, k ∈ Z или 3x -(π/4)=(2π/3)+2π*n, n ∈ Z
3x=(π/3)+(π/4)+2π*k, k ∈ Z или 3x =(2π/3)+(π/4)+2π*n, n ∈ Z
3x=(7π/12)+2π*k, k ∈ Z или 3x =(11π/12)+2π*n, n ∈ Z
[b]x=(7π/36)+(2π/3)*k, k ∈ Z [/b] или [b]x =(11π/36)+(2π/3)*n, n ∈ Z [/b]
б)
(x/3)-(π/4)= ± arccos(1/2)+2π*n, n ∈ Z
x/3=(π/4) ± (π/3)+2π*n, n ∈ Z
x=(3π/4) ± π+6π*n, n ∈ Z
x=(-π/4) +6π*n, n ∈ Z или x=(7π/4) +6π*n, n ∈ Z