SOLUTION: Hi, I am Mickey. If x is a third-quadrant angle such that tan x = 1/3, what is the exact value of cos x.

Algebra ->  Trigonometry-basics -> SOLUTION: Hi, I am Mickey. If x is a third-quadrant angle such that tan x = 1/3, what is the exact value of cos x.       Log On


   



Question 845230: Hi, I am Mickey.
If x is a third-quadrant angle such that tan x = 1/3, what is the exact value of cos x.

Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
If x is a third-quadrant angle such that tan x = 1/3, what is the exact value of cos x.
hypotenuse of reference right triangle in quadrant III=√(1^2+3^2)=√(1+9)=√10
In quadrant III, sin<0, cos<0
cosx=-3/√10=-3√10/10