Find tanθ if cosθ=-1/2 and terminates in Quadrant II.

Answer 1

cosx = -1/2 = adjacent side/hypotenuse = a/h

cosine is negative only in the 2nd or 3rd quadrant

tanx = opposite side/adjacent side = o/a = sqr3/-1 = negative sqr3 in quadrant 2

tanx = -1.732 = -square root of 3

x=120 degrees = cos^-2(-1/2) = pi/3

the opposite side = square root of (2 squared minus 1 square) = sqr(4-1) = sqr3,

but -sqr3 in the 2nd quadrant

Answer 2