Math question

Question

Math question

vera_ewing · Answer

attachment

anonymous · Answer

definitely not C

anonymous · Answer

if you do not have this memorized, do the same as before
draw a triangle, find the missing side

just_one_last_goodbye · Answer

Would love to help but this type of problems are way above my knowledge xD good luck but you got pros that are helping c;' @satellite73 and @phi

anonymous · Answer

what you need is a good unit circle cheat sheet

phi · Answer

First step, identify the "line" that represents pi radians (or 180 degrees)
ditto for 3pi/2  (270 degrees)

vera_ewing · Answer

Well I know tanθ = (sqrt)3 , so how do I find cosθ using the triangle?

anonymous · Answer

look in quadrant 3 to see where the second coordinate is $-\frac{\sqrt{3}}{2}$

anonymous · Answer

you will see that the first coordinate is $-\frac{1}{2}$ , that is the cosine

vera_ewing · Answer

Wait wouldn't it be 1/2 not -1/2 ? Since it's in Quadrant 3?

anonymous · Answer

you will also see that the angle is $\frac{4\pi}{3}$ although you were not asked for that

anonymous · Answer

no
you are below the x axis in quadrant 3, so the first coordinate is negative, as is the second

phi · Answer

|dw:1436191312914:dw|