find the exact value if any of the composite function do not

find the exact value, if any, of the composite function. do not use a calculator tan^-1(tan 11pi/12)

Solution

tan^-1(tan 11pi/12)

tan^-1(tan (pi- pi/12))

tan^-1(-tan(pi/12))

-tan^-1(tan(pi/12))

=-(pi/12)