Question

Question #1f618

Answer 1

cot`(-pi/4)=-cot(pi/4)`
sec`((7pi)/6)=sec(pi+pi/6)=-sec(pi/6)`

Explanation:

Angle `-pi/4` is in the IVth quadrant, where cot is negative,

hence cot`(-pi/4)=-cot(pi/4)`

Angle`((7pi)/6)` is in the IIIrd quadrant where cosine and hence sec is negative. This makes sec`((7pi)/6)=sec(pi+pi/6)=-sec(pi/6)`