1
x/3=π/2+πn,n∈z⇒x=3π/2+3πn,n∈z
2
3x/4-π/4=π/4+πn,n∈z
3x/4=π/2+πn,n∈z
x=2π/3+4πn/3,n∈z
3
sin(3x+π/3)=-√3/2
3x+π/3=(-1)^(n+1)*π/3+πn,n∈z
3x=-π/3+(-1)^(n+1)*π/3+πn,n∈z
x-π/9+(-1)^(n+1)*π/9+πn/3,n∈z
4
{cosx≠√3/2
{sinx=-1/2
x=7π/6+2πn,n∈z
5
{sinx≠-√3/2
{cosx=1/2
x=π/6+2πn
6
{cos2x≠1
{cos3x=0
3x=π/2+πn,n∈z
x=π/6+πn/3,n∈z
7
cos4x=-1⇒4x=π+2πn,n∈z⇒x=π/4+πn/2,n∈z
sin2x=0⇒2x=πk⇒x=πk/2,k∈z
8
cos(x+π/4)=-1⇒x+π/4=π+2πn,n∈z⇒x=3π/4+2πn,n∈z
tgx=-1⇒x=-π/4+πk,k∈z