Sin and Cos help!? ?

Question

Evaluate cot [arccos (-1/2) + arccos (0) + arctan (1/√3)]

Not sure the process of working out this problem.. please help!

10 Points today! :]

Answer 1

x=arccos (-1/2)

cosx=-1/2

y=arccos (0)

cosy=0

z=arctan (1/√3)

tan z =1/√3

cot(x+y+z)

=cos(x+y+z)/sin(x+y+z)

=?

Answer 2

x=arccos (-1/2)

cosx=-1/2

x=120degree

y=arccos (0)

cosy=0

y=90degree

z=arctan (1/√3)

tan z =1/√3

z=30degree

cot(x+y+z)= cot(120+90+30)

                =cot(240degree)

                =cot(180+60)

                =-(1/3)^1/2                  <=ans