设底角为A,顶角为B,则B=∏-2A
sinA=5/13,cosA=12/13,
sinB=sin(π-2A)=sin2A=2sinAcosA=120/169
cosB=cos(π-2A)=-cos2A=-[cos^2(A)-sin^2(A)]=-119/169
tanB=sinB/cosB=119/120
设底角为A,顶角为B,则B=∏-2A
sinA=5/13,cosA=12/13,
sinB=sin(π-2A)=sin2A=2sinAcosA=120/169
cosB=cos(π-2A)=-cos2A=-[cos^2(A)-sin^2(A)]=-119/169
tanB=sinB/cosB=119/120