a=b+2b=c+2a=c+4cosA=(b^2+c^2-a^2)/2bc=[(c+2)^2+c^2-(c+4)^2]/2(c+2)c=[c^2-4c-12]/2(c+2)c=(c-6)(c+2)/2(c+2)c=(c-6)/2c最大角的正弦值为2分之根号3sinA=√3/2(A>60)cosA=-1/2即(c-6)/2c=-1/2c=3b=3+2=5S=bcsinA/...