1、
tan(A+B-π/4)
=tan[(A+π/12)+(B-π/3)]
=[tan(A+π/12)+tan(B-π/3)]/[1-tan(A+π/12)tan(B-π/3)]
=-√2
2、
tan(A+B-π/4)
=[tan(A+B)-tanπ/4]/[1+tan(A+B)tanπ/4]
=[tan(A+B)-1]/[1+tan(A+B)]=-√2
tan(A+B)=-3+2√2