Answer:
- 2nd quadrant: 120°
- 3rd quadrant: 240°
Explanation:
Dividing by cos(x)², you get
... (sin(x)/cos(x))² = 3
... tan(x)² = 3
... tan(x) = ±√3
... x = arctan(±√3) = ±60° + k·180° for any integer k
In the 2nd quadrant, ...
... x = 180° -60° = 120°
In the 3rd quadrant, ...
... x = 180° +60° = 240°
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A graphing calculator can help you find or check answers. In most cases it works well to rewrite the equation to a form that is equal to zero. Here, we have subtracted 3cos(x)² from both sides of the equation.