first, we know that 510 is more than 360 degrees, which means it can be reduced (the reason is because, for example, the cotangent of 720° is the same as the cotangent of 360°)
510-360=150
Then find the cotangent of 150°:
1/tan(150°)
1/√3
Simplify:
1/√3 = √3/3
Your answer is √3/3.
