`tan^2(3x)=3`

`tan(3x)=+-sqrt(3)`

General solutions for tan(3x)=-`sqrt(3)` are

`3x=(2pi)/3+pin`

`x=(3pin+2pi)/9`

General solutions for tan(3x)=`sqrt(3)` are

`3x=pi/3+pin`

`x=(3pin+pi)/9`

Therefore solution are

`x=(3pin+pi)/9 , (3pin+2pi)/9`

`tan^2(3x)=3`

`tan(3x)=+-sqrt(3)`

General solutions for tan(3x)=-`sqrt(3)` are

`3x=(2pi)/3+pin`

`x=(3pin+2pi)/9`

General solutions for tan(3x)=`sqrt(3)` are

`3x=pi/3+pin`

`x=(3pin+pi)/9`

Therefore solution are

`x=(3pin+pi)/9 , (3pin+2pi)/9`