Find the value of the following:
tan−1[2cos(2sin−112)]
tan−1[2cos(2sin−112)]=tan−1[2cos{2sin−1(sinπ6)}](∵ sinπ6=12)=tan−1[2cos(2×π6)]=tan−1[2cosπ3]=tan−1[2×12]=tan−1(1) (∵cos π3=12)=tan−1(tanπ4)=π4
cot(tan−1a+cot−1a)
tan−1(tan7π6)