Without using a calculator how do you evaluate tan 5π/6.

Remember that pi=180,

so 180/6=30, 30*5=150,

what's tan 150?

Remember that 150 degrees is in the 2nd quadrant, and this is tangent, so it means the answer must be negative, because tan 150 = - tan 30, and - tan30=-√3/3.

Answer: - √3/3.