Practice problem
If and θ\thetaθ is in the 3rd3^{\text{rd}}3rd quadrant, find cos(θ)\cos(\theta)cos(θ).
34\frac{\sqrt{3}}{4}43
-34\frac{\sqrt{3}}{4}43
154\frac{\sqrt{15}}{4}415
-154\frac{\sqrt{15}}{4}415
Type a concept, like “slope” or “photosynthesis”.