cota=2 tana=1/2
tan(β-2α)=-tan(2a-b)=-tan[a+(a-b)]=-(tana+tan(a-b))/(1-tanatan(a-b))
=-(1/2-2/3)/(1+1/2*2/3)
=(1/6)/(8/6)
=1/8
cota=2 tana=1/2
tan(β-2α)=-tan(2a-b)=-tan[a+(a-b)]=-(tana+tan(a-b))/(1-tanatan(a-b))
=-(1/2-2/3)/(1+1/2*2/3)
=(1/6)/(8/6)
=1/8