Question 381387
1. Answer is A.

2. If cos x = 1/2 then sin x = sqrt(3)/2 or -sqrt(3)/2. This is due to the Pythagorean identity {{{cos^2 (x) + sin^2 (x) = 1}}}.

3. If cot x = 1 then tan x = 1. It follows that either x = pi/4 or x = 5pi/4 (if x is between 0 and 2pi)