How do you evaluate tan (120)?

1 Answer
Nghi N.
Nov 29, 2015

Evaluate tan (120)
Ans: - sqrt3

Explanation:

  1. Trig table of special arcs --> tan 120 = -sqrt3

  2. tan 120 = tan (150 - 30) = (tan (150 - tan 30)/(1 + tan 30.tan.60) =
    = (-sqrt3/3 - sqrt3/3)/[1 + (-sqrt3/3)(sqrt3/3)] =
    = ((-2)(sqrt3/3))/((1 - 1/3)) = ((-2sqrt3)/3)(3/2) = -sqrt3

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