Find the Quadrant of the Angle cos(105)
Problem
Solution
Identify the unit of the angle. Since
105 is typically used in degrees for basic trigonometry unless specified as radians, we treat it as105^∘ Determine the standard ranges for each quadrant in degrees: Quadrant I is
0^∘<θ<90^∘ Quadrant II is90^∘<θ<180^∘ Quadrant III is180^∘<θ<270^∘ and Quadrant IV is270^∘<θ<360^∘ Compare the given angle to these ranges. Since
90^∘<105^∘<180^∘ the angle falls within the second quadrant.Verify the sign of the cosine function. In Quadrant II, the
x coordinates are negative, which meanscos(105^∘) is negative.
Final Answer
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