Question

I will fan and medal!
If θ is in Quadrant IV and sinθ = -1/2, then cosθ=?
the choices are:
-(2sqrt(3)/3)
-(sqrt(3)/2)
sqrt(3)/2
(2sqrt(3)/3)

Answer 1

@Jacob902

Answer 2

draw a right triangle in quadrant 4
definition of sin \[\large\rm sin = \frac{ opposite }{ hypothounuse }\]
cos = adjacent over hypotenuse
apply Pythagorean theorem find the 3rd side of the right triangle \[\huge\rm a^2 +b^2 = c^2\]