方程是x^2+3x-2=0吧?
1、根据韦达定理：tana+tanβ=-3,tana*tanβ=-2
则tan(a+β)
=(tana+tanβ)/(1-tana*tanβ)
=-3/(1+2)
=-1
2、∵tan45°
=tan(22°+23°)
=(tan22°+tan23°)/(1-tan22°tan23°)
=1
∴tan22°+tan23°=1-tan22°tan23°
即tan22°+tan23°+tan22°tan23°=1
∴(1+tan22°)*(1+tan23°)
=1+tan22°+tan23°+tan22°tan23°
=1+1
=2