①
2*sin50°*(1+sqr(3)*tan10°)
=2*sin50°*（tan60°-tan10°）/tan(60°- 10°)
=2*cos50°*（tan60°-tan10°）
=2*cos50°*[sin60°/cos60°- sin10°/cos10° ]
=2*cos50°*sin(60°-
10°) /(cos60°*cos10°)
=2*cos50°*sin50°/(cos60°*cos10°)
=sin100°/(cos60°*cos10°)
=sin(90°+10°) /(cos60°*cos10°)
=cos10°/(cos60°*cos10°)
=1/cos60°
=2
②因为：a^2=b^2+c^2 -2bc*cosA
所以：3= b^2+c^2 -2bc/3
>=2bc -2bc/3
即：bc