Question #1f618

1 Answer
Aug 26, 2015

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)