Question

Find tan0 if cos0= -1/2 and 0 terminates in quadrant II

Answer 1

In quadrant II

cos θ = - 1 / 2

for

θ = 2 π / 3 rad (120°)


sin θ = sin 2 π / 3

sin θ = √3 / 2


tan θ = sin θ / cos θ = ( √3 / 2 ) / ( - 1 / 2 ) = - √3

Answer 2

Cos A = x/r = -1/2
x^2 + y^2 = r^2
(-1)^2 + y^2 = 2^2
Y = sqrt3.
Tan A = y/x = sqrt3/-1 = -sqrt3.