Assuming cos2(α) is cos^2(a), the anything squared is always positive. Therefore, the only part that affects the answer is which quadrants cot(α)<0 in. Use a reference angle in each quadrant.
cot(α)=adj/opp
Quadrant I
cot(α)=positive/positive
Not less than 0
Quadrant II
cot(α)=negative/positive
Is less than 0
Quadrant III
cot(α)=negative/negative
Not less than 0 (the negatives will cancel out and form a positive)
Quadrant IV
cot(α)=positive/negative
Is less than 0
Your answer would be that quadrants II and IV satisfy the conditions cot(α)<0 and (even though it is useless to have) cos^2(α)>0.
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Assuming cos2(α) is cos^2(a), the anything squared is always positive. Therefore, the only part that affects the answer is which quadrants cot(α)<0 in. Use a reference angle in each quadrant.
cot(α)=adj/opp
Quadrant I
cot(α)=positive/positive
Not less than 0
Quadrant II
cot(α)=negative/positive
Is less than 0
Quadrant III
cot(α)=negative/negative
Not less than 0 (the negatives will cancel out and form a positive)
Quadrant IV
cot(α)=positive/negative
Is less than 0
Your answer would be that quadrants II and IV satisfy the conditions cot(α)<0 and (even though it is useless to have) cos^2(α)>0.