Question

What is cot 75 degrees?

Answer 1

Use the trig identity: `tan (a + b) = (tan a+ tan b)/(1 - tan a.tan b)`

`tan 30 = sqrt3/3`; tan 45 = 1

`tan 75 = tan (30 + 45) = (3 + sqrt3)/3.(3)/(3 - sqrt3) = (3 + sqrt3)/(3 - sqrt3)`