设a=tanα,b=tanβ ,c=tanγ,α,β ,γ ∈（0,π/2）,则p=2（cosα）^2-2(cosβ )^2+3(cosγ)^2=cos2α-cos2β+ 3(cosγ)^2=2sin(α+β)sin(β-α)+3(cosγ)^2.由abc+a+c=b得b=(a+c)/(1-ac)即tanβ=(tanα+tanγ)/(1...