Question 371827
a) cotx = -1, same as tanx = -1, from 0 to {{{2pi}}}, the only solutions are {{{3pi/4}}} and {{{7pi/4}}}.

b)  The equation is the same as cosB = 1/2. From 0 to {{{2pi}}}, the only solutions are {{{2pi/3}}} and {{{4pi/3}}}.