Evaluate tan 13π12
We have
tan 13π12 = tan (π+π12)
= tanπ12[∵tan(π+θ)=tan θ]
= tan(π3−π4)
= tanπ3−tanπ41+ tan π3 tan π4=√3−11+√3
= (√3−1)(√3+1)×(√3−1)(√3−1)=(√3−1)2(3−1)
= (3+1−2√3)2=(4−2√3)2=(2−√3)