Okay. So you have this:
. . . . .\(\displaystyle \tan(x)\, -\, \cot(x)\, =\, 2\, \sqrt{\strut 3\,}\)
You know that:
. . . . .\(\displaystyle \cot(x)\, =\, \dfrac{1}{\tan(x)}\)
Using this identity, you can get to here:
. . . . .\(\displaystyle \tan(x)\, -\, \dfrac{1}{\tan(x)}\, =\, 2\, \sqrt{\strut 3\,}\)
Combine the two terms (the tangent and the tangent-fraction) into one:
. . . . .\(\displaystyle \dfrac{\tan^2(x)\, -\, 1}{\tan(x)}\, =\, 2\, \sqrt{\strut 3\,}\)
Multiply through and move everything over onto one side of the "equals" sign. You'll get a quadratic in tangent. Solve for the values of tan(x), and choose the correct solution for the specified interval. Then find the value for cot(x). Then sum.
If you get stuck, please reply showing your thoughts and efforts so far. Thank you!